Contents
2011
Volume: 31 Issue 6
50 Article(s)
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Atmospheric Optics and Oceanic Optics
Research on Micro-Lens Coupling System of All-Fiber Raman Lidar
Li Shichun, Hua Dengxin, Song Yuehui, and Wang Peng
The coupling efficiency of the backscattering optical field received by the telescope into single-mode fiber is one of the significant parameters affecting all-fiber Raman lidar system. By analyzing the mathematical model of coupling the free space plane optical field into single-mode fiber, the influence of the telescThe coupling efficiency of the backscattering optical field received by the telescope into single-mode fiber is one of the significant parameters affecting all-fiber Raman lidar system. By analyzing the mathematical model of coupling the free space plane optical field into single-mode fiber, the influence of the telescope central obstacle in the coaxial lidar on the optimum coupling efficiency is clarified. And then it is numerically analyzed the change of the coupling efficiency with the variation of the alignment errors such as the lateral offset, tilt angle and defocus error with different obstacle ratios. Furthermore, based on these conclusions, an initial optical system is constructed for the telescope coupling system optimization. By adding and choosing suitable lenses and micro lenses and optimizing the configuration parameters, the total coupling efficiency of 17% with the Cassegrain telescope is enhanced to 50% when the obstacle ratio is 0.288. Two coupling configurations with micro lens arrays and fiber arrays are designed to improve the coupling energy of light signal. Simulation results show that the coupling efficiency and energy may be improved using the new telescope coupling system with micro lens array and single-mode fiber array..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 601001 (2011)
Fiber Optics and Optical Communications
Parametric Amplification and Raman Scattering in Photonic Crystal Fiber
Wang Xuying, Jia Weiguo, Yin Jianquan, Tong Laga, Menke Neimule, Yang Jun, and Zhang Junping
Photonic crystal fiber (PCF) has excellent features compared with the traditional optical fiber, especially nonlinear effect and birefringence effect. By quoting Lorentzian model of Raman gain spectra in PCF, the gain spectra are studied under the action of Raman scattering together with parametric amplification, when Photonic crystal fiber (PCF) has excellent features compared with the traditional optical fiber, especially nonlinear effect and birefringence effect. By quoting Lorentzian model of Raman gain spectra in PCF, the gain spectra are studied under the action of Raman scattering together with parametric amplification, when the pump wave polarization is oriented at 45° between the axes. The result shows that the input power and the group velocity mismatching have a great influence on the gain spectra because of the interaction between parametric amplification and Raman scattering. The gain spectrum bandwidth widened and the intensity enhanced as the input power and the group-velocity mismatching enlarged. Stokes-wave is multiple-peaked structure when input power is greater and stable in anomalous dispersion regime .The Stokes-waves gain are greater than anti-Stokes waves gain in normal dispersion regime. The pump wave can be changed into pulse array under certain conditions so that the T-frequency pluses can be extracted from it..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 606001 (2011)
Homodyne Detection of Distance and Velocity by Chirped-Amplitude Modulated Lidar
Yu Xiao, Hong Guanglie, Ling Yuan, and Shu Rong
A system of coherent ladar which is based on chirp amplitude modulation is built. The system is made up of narrow-line-width laser, Mach-Zehnder intensity modulator, and fiber homodyne detection optics. The measurement of velocity and distance of the target is completed based on chirp signal generated by direct digitalA system of coherent ladar which is based on chirp amplitude modulation is built. The system is made up of narrow-line-width laser, Mach-Zehnder intensity modulator, and fiber homodyne detection optics. The measurement of velocity and distance of the target is completed based on chirp signal generated by direct digital synthesis(DDS), both the resolution and error of velocity and range are measured and analyzed, and research on relation between signal-to-noise ratio (SNR) and system detection power is also completed. Experimental data indicates that velocity accuracy reaches mm/s, range accuracy reaches cm and sensitivity is better than 0.1 nW..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 606002 (2011)
Performance Improvement of Optical Single Sideband with Carrier Signals in Radio over Fiber System
Liu Xiangling, Liu Zengji, Li Jiandong, and Yue Peng
An improved method to generate optical single sideband with carrier (OSSB+C) signals is proposed based on the integrated Mach-Zehnder modulator(MZM) in the radio over fiber (RoF) system, avoiding the great difference of the power of optical carrier and that of optical sideband using the conventional OSSB+C modulation. An improved method to generate optical single sideband with carrier (OSSB+C) signals is proposed based on the integrated Mach-Zehnder modulator(MZM) in the radio over fiber (RoF) system, avoiding the great difference of the power of optical carrier and that of optical sideband using the conventional OSSB+C modulation. By adjusting the direct current voltage applied in the direct current arm of the integrated MZM, the balanced power of the optical carrier and optical sideband is obtained for any modulation index, i.e. the optimum carrier-to-sideband ratio (CSR) value of 0 dB is achieved. The variation of CSR is then analyzed theoretically under different loss states of the integrated MZM. It is verified by the simulation results that adjusting the direct current voltage can make the power of optical carrier and that of optical sideband balanced. The simulation results also show that when the direct voltage deviates from the optimum value in the integrated MZM, the RoF system based on the proposed technique has better robustness if the bias drift is controlled within the range of 5%..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 606003 (2011)
Doubly Cladding Single-Mode Optical Fiber Sensors and its Application in Temperature and Humidity Sensing
Zhang Xiaokang, Ye Xiaojing, and Chen Zhidong
A new type of sensor based on a doubly cladding single-mode optical fiber is proposed. The measurable range of the refractive index changes for the sensors is analyzed theoretically and demonstrated experimentally, which corresponds to the case that the fundamental mode in the fiber becomes leaky. Based on the analysisA new type of sensor based on a doubly cladding single-mode optical fiber is proposed. The measurable range of the refractive index changes for the sensors is analyzed theoretically and demonstrated experimentally, which corresponds to the case that the fundamental mode in the fiber becomes leaky. Based on the analysis for the theoretical and the experimental results, the principle of the sensor is got. The output of the optical power of the sensor is almost inversely proportional to the refractive index of the outer cladding in some range of variation after the base mode in the fiber becoming leaky. A sensor with a linear response in the temperature range of 55~105 ℃ and an optical power variation of 39 dB is obtained. A new method of recoating hydrogels on optical fibers is verified. A humidity sensor fabricated by agarose shows a power variation of 9 dB in the moisture range of 30%~100%RH and insertion loss of 0.5 dB..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 606004 (2011)
Research on Achieving Arbitrary Phase Shifts in Fiber Bragg Grating by Changing Refractive Index of Fiber Directly
Wang Hongbo, Pu Tao, Lu Lin, Fang Tao, and Sun Guodan
A new way of achieving phase shifts in fiber Bragg grating (FBG) by increasing direct current refractive index of the FBG is proposed. Simulation and experimental results show that arbitrary phase shifts can be achieved by the presented method. Comparison between the proposed direct-current phase-shift and traditional A new way of achieving phase shifts in fiber Bragg grating (FBG) by increasing direct current refractive index of the FBG is proposed. Simulation and experimental results show that arbitrary phase shifts can be achieved by the presented method. Comparison between the proposed direct-current phase-shift and traditional discrete phase-shift FBG is made, which shows a good agreement. 7- and 63-chip optical code-division multiple-access en/decoders are fabricated. The fine en/decoding performance verifies the feasibility of fabricating multi-phase shifted FBG by the proposed method. High-precision and phase mask are not required in fabrication. This method has advantages in cost-effectiveness, flexibility and simplicity compared to traditional ways..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 606005 (2011)
Study of Phase-Shifted Long Period Grating Performed by Adding Modulated Structure
Li Xiaolan, Zhang Weigang, Zhang Shanshan, Fan Hongjian, and Yin Limei
We propose a new method to design novel structure of phase-shifted long period grating by adding a modulated structure in a long period grating somewhere, which performs an accumulated phase shift. Based on the phase-match theory, the relation between the phase shift and parameters of the grating is derived, while the We propose a new method to design novel structure of phase-shifted long period grating by adding a modulated structure in a long period grating somewhere, which performs an accumulated phase shift. Based on the phase-match theory, the relation between the phase shift and parameters of the grating is derived, while the modulated structure is a uniform short grating and its modulated depth remains the same. This new theory is simulated with the transmission matrix method and the validity is proved by experimental fabrication with CO2 laser. The study shows that adding a uniform short grating in a long period grating can form a phase-shift long period grating. And the spectrum only depends on the length of modulated sturcture, in the case that its modulated depth of refractive index is the same as the original one..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 606006 (2011)
Simulation on Single-Frequency Raman Fiber Amplifiers Utilizing Multi-Stage Amplification Scheme
Leng Jinyong, Wu Wuming, Chen Shengping, Hou Jing, and Xu Xiaojun
High-power operation of single-frequency Raman fiber amplifiers (SF-RFA) is usually limited by the onset of stimulated Brillouin scattering (SBS). Simulation results indicate that the output power of a single-stage SF-RFA is always low and the needed pump power is too high to satisfy. The amplifiers with multiple stageHigh-power operation of single-frequency Raman fiber amplifiers (SF-RFA) is usually limited by the onset of stimulated Brillouin scattering (SBS). Simulation results indicate that the output power of a single-stage SF-RFA is always low and the needed pump power is too high to satisfy. The amplifiers with multiple stages have comparatively higher output power and efficiency. Different types of fiber should be provided in different stages so that the output power could be optimized according to the attainable pump power. Taking a two-stage amplifier as an example, 100 m fiber with the core diameter of 6 μm is used in the first stage. By utilizing strain gradients along the fiber to suppress the SBS, the output of the first stage is increased to 3 W under the pump power of 32 W. The output power of the first stage is seeded into the second stage with an isolator between them. The second stage is composed by 70 m fiber with the core diameter of 15 μm. By suppressing the SBS with strain gradients, 20 W and 30 W output powers are obtained with the pump powers of 105 W and 130 W, respectively..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 606007 (2011)
Influence of Stokes Pulse Shapes on SBS Slow Light in Fibers
Hou Shanglin, Li Hongbing, Li Suoping, Liu Yanjun, and Xu Yongzhao
In order to increase time delay and decrease pulse broadening via stimulated-Brillouin scattering slow light, the coupled amplitude equations of stimulated Brillouin scattering in optical fibers are solved with fourth-order Runge-Kutta formula and characteristic-line mothod, the influence of the edge sharpness, magnituIn order to increase time delay and decrease pulse broadening via stimulated-Brillouin scattering slow light, the coupled amplitude equations of stimulated Brillouin scattering in optical fibers are solved with fourth-order Runge-Kutta formula and characteristic-line mothod, the influence of the edge sharpness, magnitude and duration of injected Stokes pulse on time delay and pulse broadening factor are investigated. A method of optimizing time delay and pulse broadening factor is represented, namely, increasing the sharpness of Stokes pulse appropriately. Comparing with using Gaussian pulse as injected Stokes pulse, the similar time delay and less pulse broadening factor are obtained by this method. Theoretical analysis based on different power of injected Stokes pulse proves that improving the sharpness of injected Stokes pulse contributes a lot to reduce pulse broadening factor..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 606008 (2011)
Imaging Systems
Non-Axial Characteristics of Strehl Ratio of Cubic Phase Mask in Wavefront Coding System
Fan Zhigang, Chen Shouqian, Chang Hong, and Xu Zhigao
For general imaging optical system, the peak position of point spread function (PSF) is located in the optical axis. Strehl ratio (SR) is defined as the ratio of on-axis values of PSF with and without aberrations, but PSF of wavefront coding system whose phase change in pupil plane is asymmetric has a shift in the imagFor general imaging optical system, the peak position of point spread function (PSF) is located in the optical axis. Strehl ratio (SR) is defined as the ratio of on-axis values of PSF with and without aberrations, but PSF of wavefront coding system whose phase change in pupil plane is asymmetric has a shift in the image plane, so evaluation of wavefront coding system using traditional Strehl ratio is not appropriate. Shift value of PSF for cubic phase mask is carried out, which is a family of parabolas, whose focal plane is symmetrical axis. Based on this, non-axial Strehl ratio of wavefront coding system is defined, whose different parameters are analyzed, and the magnitude of Strehl ratio is inversely proportional to parameter of phase mask. Non-axial Strehl ratio is used to evaluate consistency and recoverability of PSF. Finally, an evaluation method in order to optimize phase mask parameter is given, which can determine the relation between consistency and recoverability of PSF and phase mask parameter..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 6, 611001 (2011)
Design of Collective Optic System for Thomson Scattering Measurements on Shenguang-Ⅲ Facility
Yan Yadong, Lu Weitao, Dong Xiaona, He Junhua, Liu Xizhan, Zhang Min, and Zhang Pengshun
A Thomson scattering signal collective optic system is designed for Thomson scattering measurements on Shenguang-Ⅲ facility. The optical system is composed of two coupled Cassegrain systems, and has an intermediate image plane. This configuration makes the optical path length long enough to transmit the scattering signA Thomson scattering signal collective optic system is designed for Thomson scattering measurements on Shenguang-Ⅲ facility. The optical system is composed of two coupled Cassegrain systems, and has an intermediate image plane. This configuration makes the optical path length long enough to transmit the scattering signal to the camera outside the target chamber. The catadioptric system makes it easier to balance chromatic aberration as there are few ultraviolet materials available. The corrector lens which has a long focal length is replaced by two faster corrector lenses, which make the fabrications and measurements easier. The obscuration ratio is reduced by choosing a proper intermediate magnification. The two refraction lenses beside the intermediate image plane help to couple the two systems well. A reticle is set at the intermediate image plane for system aiming and can be removed before event recording. This system has the total length of more than 5 m, with the maximal elements diameter of 190 mm. The field of view is 2 mm, the magnification is 1.5, and the object space F-number is 10, and the resolution is better than 20 μm..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 611002 (2011)
General Self-Imaging Properties for Line-Tapered Multimode Interference Couplers
Le Zichun, Huang Sungang, Hu Jinhua, Fu Minglei, and Zhang Ming
The line-tapered multimode interference couplers which are more compact than traditional multimode interference couplers had been widely used in integrated optical components. The self-imaging properties are the most important characteristics for their applications in integrated optical components. Based on the self-imThe line-tapered multimode interference couplers which are more compact than traditional multimode interference couplers had been widely used in integrated optical components. The self-imaging properties are the most important characteristics for their applications in integrated optical components. Based on the self-imaging of multimode interference couplers, we analyze the general self-imaging properties in line-tapered multimode interference couplers in detail, and find the positions of images which directly relate to the position of input field, the position number, the initial width of line-tapered multimode interference couplers and transition ratio. The analytical expression of image positions and some characteristics are summarized. Finally, the guide-mode propagation analysis and finite-difference beam propagation method (FDBPM) are used to confirm the analytical results. These conclusions can be used to exactly get the positions of images without complex calculation, which provide a theoretical basis and design reference of integrated optical components with line-tapered multimode interference couplers..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 611003 (2011)
Image Restoration of Cassegrain Optical Remote Sensing System
Xie Dingjie, Li Tiecheng, Feng Huajun, Li Xiaotong, and Xu Zhihai
Cassegrain optical remote sensing system is a combination of telescope system and annular aperture. Its Fraunhofer diffraction of infinite objects is the joint result of circular hole diffraction and circular screen diffraction. Because of the loss of diffraction due to central obscuration of circular screen, modulatioCassegrain optical remote sensing system is a combination of telescope system and annular aperture. Its Fraunhofer diffraction of infinite objects is the joint result of circular hole diffraction and circular screen diffraction. Because of the loss of diffraction due to central obscuration of circular screen, modulation transfer function (MTF) of the system degrades greatly in middle frequency, and this directly affects the imaging quality. A Cassegrain optical remote sensing system is designed whose focal length is 2 m. In order to make up for the loss of the image quality, a modulation transfer function compensation (MTFC) technology is used, in which the point spread function (PSF) of image is obtained by slanted-edge method, to recovery image. Some assessment functions are used to evaluate the recovery results. The experimental results indicate that the image quality is improved obviously..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 611004 (2011)
Combined Nonuniformity Correction Algorithm of Infrared Focal Plane Arrays
Hong Wenqing, Yang Nansheng, Wang Xiaodong, Su Junbo, Su Lan, and Hu Zhibin
The advantages and disadvantages in nonuniformity correction (NUC) algorithms based on calibration and scene of infrared focal plane arrays (IRFPA) are analysed separately. The combined NUC algorithm is presented. Two-point NUC algorithm based on calibration is adopted to remove the nonuniformity of the detector simplyThe advantages and disadvantages in nonuniformity correction (NUC) algorithms based on calibration and scene of infrared focal plane arrays (IRFPA) are analysed separately. The combined NUC algorithm is presented. Two-point NUC algorithm based on calibration is adopted to remove the nonuniformity of the detector simply. The influences of detectors′ NUC parameters which will change with time are weakened by using the scene-based temporal high-pass filter algorithm and new-style adaptive filter algorithm. The disadvantages for image quality introduced by noises are weakened too. The experimental results show that the combined NUC algorithm is more stable and better than some NUC algorithms with great value in project applications, such as two point NUC algorithm, temporal high-pass filter NUC algorithm and former adaptive filter NUC algorithm..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 611005 (2011)
Instrumentation, Measurement and Metrology
Variable-Focus Hysteresis of Double-Liquid Variable-Focus Lens
Wang Dazhen, Peng Runling, Chen Jiabi, and Zhuang Songlin
By introducing the contact-line static friction, a mechanical model for the contact line in a double-liquid variable-focus lens is established, which is a liquid-liquid-solid three phase system. The mechanical analysis on the contact line of the liquid-liquid-solid three phase system with non-ideal state is done again.By introducing the contact-line static friction, a mechanical model for the contact line in a double-liquid variable-focus lens is established, which is a liquid-liquid-solid three phase system. The mechanical analysis on the contact line of the liquid-liquid-solid three phase system with non-ideal state is done again. On this basis, the Young′s equation is modified, and a reasonable explanation is given for the phenomenon of variable-focus hysteresis. The variable-focus experiment of the double-liquid variable-focus lens with dielectric layer thickness of 2 μm under the applied voltages is performed. A hysteresis curve between the focal length of the double-liquid variable-focus lens and the applied voltage is given. The experimental result agrees very well with the theoretical analysis..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 612001 (2011)
Stack-Yard 3D Measurement Based on Photogrammetry and Projected Contour Aiding
Zhang Xiaohu, Ou Jianliang, Yuan Yun, Ma Qinhua, Zhu Zhaokun, and Yu Qifeng
Fast and accurate 3D measurement of large stack-yard is important job in bulk load-and-unload and logistics management. Stack-yard holds its special features as complex and irregular shape, single surface texture and low material reflectivity, thus its 3D measurement is quite difficult to be realized by non-contacting Fast and accurate 3D measurement of large stack-yard is important job in bulk load-and-unload and logistics management. Stack-yard holds its special features as complex and irregular shape, single surface texture and low material reflectivity, thus its 3D measurement is quite difficult to be realized by non-contacting technologies, such as LiDAR and photogrammetry. Light section is good at the measurement of small bulk-flow but not suitable for large-scale bulk yard yet. An improved method based on stereo cameras and laser-line projector is proposed. The due theoretical model and algorithm include: corresponding point of contour edge matching in stereo imagery based on gradient and epipolar-line relation, 3D point-set calculating for stereo imagery projected-contour edge with least square adjustment and forward intersection, then 3D contour reconstructed by random sampling consensus (RANSAC) and contour spatial features from 3D point set of single contour edge. In this way, stack-yard surface can be scanned easily by the laser-line projector, and certain region′s 3D shape can be reconstructed automatically by stereo cameras on an observing position. Experiment proves that the proposed method is effective for bulk-yard 3D measurement in fast, automatic, reliable and accurate way..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 612002 (2011)
Calibration of Oblique-Reflection Aberration in Point-Diffraction Interferometer for High-Precision Spherical Surface Testing
Wang Daodang, Yang Yongying, Chen Chen, and Zhuo Yongmo
Based on the polarization effect of metal-dielectric reflector in the point-diffraction interferometer for high-precision spherical surface testing, the oblique-reflection wavefront aberration of beams with different polarizaed states at various aperture angles is analyzed in detail. According to the numerical simulatiBased on the polarization effect of metal-dielectric reflector in the point-diffraction interferometer for high-precision spherical surface testing, the oblique-reflection wavefront aberration of beams with different polarizaed states at various aperture angles is analyzed in detail. According to the numerical simulation result, the characteristic of oblique-reflection phase shift introduced by metal-dielectric reflector is studied, based on which the corresponding calibration method is presented. The experimental validation with the point-diffraction interferometer for high-precision spherical surface testing is carried out. Experimental results indicate that the metal-dielectric reflector introduces various effects on the beams with different polarized states, and the oblique-reflection wavefront aberration can be calibrated by the proposed method, with the residual error peak-valley (PV) value dropping from 0.0452λ to 0.0194λ and root mean square (RMS) value from 0.0075λ to 0.0021λ (λ is wavelength)..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 612003 (2011)
Three-Dimensional Shape Measurement Technique Based on Complementary Color-Encoded Fringe Projection
Wang Luyang, and Da Feipeng
In order to measure the object with colorful surface whose surface color may interfere with the color distinguish of projected fringe pattern, a novel method based on complementary color-encoded fringe projection is proposed. Two fringe patterns are projected onto the object in sequence. The first frame is encoded in aIn order to measure the object with colorful surface whose surface color may interfere with the color distinguish of projected fringe pattern, a novel method based on complementary color-encoded fringe projection is proposed. Two fringe patterns are projected onto the object in sequence. The first frame is encoded in a hybrid way which is with the sinusoidal color fringe and with the color coding information. The second frame is other color fringe pattern whose color is the previous encoding color′s complementary one in each according pixel. Based on the color complementary feature of the two patterns, the color information of each pixel in the captured color-encoded sinusoidal fringe image can be established with the assistance of the complementary color pattern, so that the interference of object′s color can be eliminated. Phase retrieval is done by the Fourier transform method applied to the sinusoidal fringe and unwrapped according to the color coding information. Experimental results show that the proposed technique is valid and can be applied to the measurement of colorful object..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 612004 (2011)
Spatial-Gradient-Based Digital Volume Correlation Technique for Internal Deformation Measurement
Pan Bing, Wu Dafang, Xie Huimin, and Hu Zhenxing
Digital volume correlation (DVC) measures the internal deformation of an object by analyzing two volumetric images in unit of voxel. In the practical implementation of DVC, integer-voxel displacement can be readily acquired by use of a simple searching scheme performed in spatial domain. How to achieve sub-voxel accuraDigital volume correlation (DVC) measures the internal deformation of an object by analyzing two volumetric images in unit of voxel. In the practical implementation of DVC, integer-voxel displacement can be readily acquired by use of a simple searching scheme performed in spatial domain. How to achieve sub-voxel accuracy has been considered as the key to improve the accuracy of DVC measurements. A spatial-gradient based sub-voxel algorithm is proposed, and the principle of the algorithm is described in detail. The sub-voxel algorithm is investigated in terms of accuracy and computational efficiency using computer generated volume data and actual volume images recorded using laser scanning confocal microscope. Results show that the proposed algorithm can be used as a simple yet effective technique for accurate internal deformation measurement..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 612005 (2011)
A New Method to Measure Half-Wave Voltage of Phase Modulator Based on Sagnac Optical-Fiber Interferometer
Wei Zhengjun, Li Huazeng, Wang Jindong, and Liu Songhao
LiNbO3 traveling-wave phase modulator can be used in many fields, such as optical fiber communication, phase-coding quantum key distribution system, and so on. The measurement precision of the half-wave voltage seriously affects the performance of its applied system. A new method is proposed to measure the half-wave voLiNbO3 traveling-wave phase modulator can be used in many fields, such as optical fiber communication, phase-coding quantum key distribution system, and so on. The measurement precision of the half-wave voltage seriously affects the performance of its applied system. A new method is proposed to measure the half-wave voltage based on the Sagnac optical-fiber interferometer according to the phase modulator′s applying model in quantum key distribution system. The data should be reliable compared with other methods because the same modulating pattern is adopted as the quantum key distribution system. This method is demonstrated experimentally with the precision of 10 mV by measuring the half-wave voltage of the phase modulator from Sumitomo corporation, which is used in the differential phase shift quantum key distribution system, and the obtained quantum bit error rate is lower than that of the conventional extreme measure method. This method can be helpful to measure the half-wave voltage of the phase modulator and the loading of phase voltage in the quantum key distribution system..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 612006 (2011)
Testing of Aspheric Surface Normal Vector Based on Phase Measuring Deflectometry
Zhao Wenchuan, Fan Bin, Wu Fan, Su Xianyu, and Chen Wenjing
The aspheric normal intersects the optical axis at different points with different angles and the surface can be expressed by the normal. The method based on phase measuring deflectometry (PMD) for testing the surface normal is presented. The aspheric surface under test shifts accurately along the optical axis relativeThe aspheric normal intersects the optical axis at different points with different angles and the surface can be expressed by the normal. The method based on phase measuring deflectometry (PMD) for testing the surface normal is presented. The aspheric surface under test shifts accurately along the optical axis relative to the measurement system. The camera observes the patterns reflected off the testing mirror at every scanning position while scanning the testing aspheric surface along the optical axis. Through the phase distributions, the relation between the intersection point and the angle of the surface normal with the optical axis can be gotten. In this method, the surface can also be expressed in the orthogonal coordinate..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 612007 (2011)
Wavelength Dependence of the Spectral Irradiance of Standard Lamp and Bi-Reflection Distribution Function of Diffuser Based on Standard Detectors
Yang Xiaohu, Wang Shurong, Huang Yu, Qu Yi, and Lin Guanyu
In the normal spectral radiance calibration of the internal illumination integrating sphere based on the spectral irradiance of the standard lamp, a deviation changing with wavelength exists in the ratio of instrument′s spectral radiance responsivities derived by two methods. The absolute radiance and irradiance radiomIn the normal spectral radiance calibration of the internal illumination integrating sphere based on the spectral irradiance of the standard lamp, a deviation changing with wavelength exists in the ratio of instrument′s spectral radiance responsivities derived by two methods. The absolute radiance and irradiance radiometers based on the standard detectors are built up. By calibrating standard lamp of spectral irradiance and standard diffuser with these apparatuses at four wavelengths, it is found that the actual spectral irradiance of the standard lamp is greater while the actual bi-reflection distribution function (BRDF) of the diffuser is smaller than the self-calibrated value. After correcting the standard spectral irradiance and BRDF to the spectral radiance of the integrating sphere and the instrument′s spectral radiance responsivity, the ratio derives to constant 1. Analysis shows a combined standard uncertainty of 0.884%~1.217% for the spectral radiance and 0.768%~1.136% for the spectral irradiance measurement at the four wavelengths..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 612008 (2011)
Integrated Optics
Influence of Coupling Conditions on Time Delay Line Characteristics of Integrated Waveguide Microring Resonators
Han Xiuyou, Zhang Jianing, Song Hongyan, Wu Pengsheng, Wang Linghua, Teng Jie, Li Shanfeng, and Zhao Mingshan
The influence of coupling conditions of parallel-cascaded waveguide ring resonators on the time delay applications in the optically phased array antenna systems is analyzed. Two kinds of coupling conditions, over-coupling and restriction-free, are considered to achieve a certain target delay time by parallel-cascaded tThe influence of coupling conditions of parallel-cascaded waveguide ring resonators on the time delay applications in the optically phased array antenna systems is analyzed. Two kinds of coupling conditions, over-coupling and restriction-free, are considered to achieve a certain target delay time by parallel-cascaded three ring resonators. The results show that the restriction-free coupling condition is better than the over-coupling one to obtain a flat time delay and amplitude response in the target delay bandwidth especially for the small target delay time, which is the advantage of ring-resonator-based tunable true time delay line..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 613001 (2011)
Lasers and Laser Optics
Research on Optical Parametric Oscillator Based on Periodically Poled LiTaO3 Crystal
Wei Xingbin, Peng Yuefeng, Wang Weimin, Chen Xingwu, Wang Chunhua, and Xie Gang
The theoretical analysis and experimental research of the optical parametric oscillator (OPO) based on periodically poled LiTaO3 (PPLT) crystal are presented. The wavelength tuning curves of PPLT-OPO are calculated through the coupling equations of the three-wave mixing. The output characters of signal singly resonant The theoretical analysis and experimental research of the optical parametric oscillator (OPO) based on periodically poled LiTaO3 (PPLT) crystal are presented. The wavelength tuning curves of PPLT-OPO are calculated through the coupling equations of the three-wave mixing. The output characters of signal singly resonant oscillator (SSRO) and idler singly resonant oscillator (ISRO) are studied. When the pump power of the NdYAG 1.064 μm laser is 48 W with a repetition rate of 5 kHz, the output powers of 3.9 μm laser from SSRO and ISRO are 5.78 W and 5.07 W, and corresponding conversion efficiencies are 12% and 10.6% respectively. The near-field distribution and beam quality of the 3.9 μm laser from ISRO are better than those from SSRO..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 614001 (2011)
Fourier-Domain-Mode Locking Swept Laser Source
Chen Minghui, Ding Zhihua, Wu Tong, Wang Chuan, and Hong Wei
A Fourier-domain mode locking (FDML) swept laser source is reported. The swept laser source is composed of a laser resonator and a power amplification unit. The laser resonator includes gain medium, tunable filter and delay line. Serial implementation of two semiconductor optical amplifiers is adopted in the laser as gA Fourier-domain mode locking (FDML) swept laser source is reported. The swept laser source is composed of a laser resonator and a power amplification unit. The laser resonator includes gain medium, tunable filter and delay line. Serial implementation of two semiconductor optical amplifiers is adopted in the laser as gain amplification. The tunable filter consists of polygon scanner and grating in Littrow configuration. The tuning speed of the developed swept laser centered at 1290 nm is 14.8 kHz with an average output power of 3 mW. The tuning range is 108 nm with 3 dB bandwidth of 61 nm. Swept laser source is one key element in optical-frequency-domain imaging system, and the development of this FDML swept laser source will promote the development of real time optical-frequency-domain imaging technology..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 614002 (2011)
Materials
Design and Fabrication of a Kind of Far Infrared and 10.6 μm Laser Band Compatible Camouflage Material Based on Photonic Crystals
Gao Yongfang, Shi Jiaming, Zhao Dapeng, and Wang Jiachun
Due to the change of modern detecting systems from the single working mode to the compound workingone, materials with special spectral characteristics are required to meet camouflage demands. As a new kind of man-made structural function material, photonic crystals can realize thermal infrared camouflage because of itsDue to the change of modern detecting systems from the single working mode to the compound workingone, materials with special spectral characteristics are required to meet camouflage demands. As a new kind of man-made structural function material, photonic crystals can realize thermal infrared camouflage because of its high-reflection photon forbidden band. Based on one-dimensional doped photonic crystal, a kind of far infrared and laser band compatible camouflage material is designed, then the transmission spectrum is calculated by characteristic matrix method of thin-film optical theory. The sample of photonic crystal is fabricated. It is found that the actual testing curve is coincident with the theoretic design curve. The result shows that one-dimensional doped photonic crystal can achieve far infrared and laser band compatible camouflage..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 616001 (2011)
Control of Goos-Hnchen Displacement on Bilayer Structure Composed of Single Negative Materials
Zhang Xi, Xu Jingping, and Yang Yaping
Goos-Hnchen effect which occurs on the surface of bilayer composed of electric-negative-material (ENM) slab and magnetic-negative-material (MNM) slab is analyzed by using the reflective-phase method and the Gaussian-beam peak-shift criterion. And by using the transfer matrix, it is found that the directions of Goos-HGoos-Hnchen effect which occurs on the surface of bilayer composed of electric-negative-material (ENM) slab and magnetic-negative-material (MNM) slab is analyzed by using the reflective-phase method and the Gaussian-beam peak-shift criterion. And by using the transfer matrix, it is found that the directions of Goos-Hnchen displacement are different between the situation when the beams reflect from the ENM and the situation that happen on MNM. It also shows that the Goos-Hnchen displacement of such bilayer can be controlled expediently by adjusting the thickness of one layer as the indices of ENM slab are opposite to those of MNM slab..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 616002 (2011)
First Principles Study of Electronic Structure and Optical Properties for Co-doped β-FeSi2
Yan Wanjun, Zhou Shiyun, Xie Quan, Gui Fang, Zhang Chunhong, and Guo Xiaotian
By using the first principle pseudo-potential plane-wave method based on the density function theory, geometrical structure, electronic structure and optical properties of Co-doped β-FeSi2 are calculated and analyzed. The calculated results of the geometrical structure and electronic structure show that the lattice conBy using the first principle pseudo-potential plane-wave method based on the density function theory, geometrical structure, electronic structure and optical properties of Co-doped β-FeSi2 are calculated and analyzed. The calculated results of the geometrical structure and electronic structure show that the lattice constant a increases while b and c have little change, the volume of lattice expands, the band structure changes from indirect to direct and the band gap reduces from 0.74 eV to 0.07 eV with increasing of Co from 0 to 0.25. Moreover, it was found that Co-doping can increase the volume of β-FeSi2, which also reduces the band gap. Optical properties calculation indicates that after doping Co, the imaginary part of the dielectric function ε2(ω) moves to a lower energy, the intensity in optical transition decreases, the optical absorption edge generates a red shift, and the optical band gap decreases with increasing concentrations of Co. These results offer theoretical data for design and application of optoelectronic material of β-FeSi2..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 616003 (2011)
Influence of Pressure Effect on CdS Electronic Structure and Optical Properties
Li Chunxia, Dang Suihu, Zhang Keyan, and Tu Linjun
The lattice constant, the total energy, density of state, energy band structure, optical reflection and absorption properties of the zinc blende structure CdS under different pressure are calculated by using the generated gradient approximation (GGA) method based on density functional theory. Comparison of the electronThe lattice constant, the total energy, density of state, energy band structure, optical reflection and absorption properties of the zinc blende structure CdS under different pressure are calculated by using the generated gradient approximation (GGA) method based on density functional theory. Comparison of the electronic properties of CdS at high pressure with the energy band structural information indicates that a non-structural transition occurs at about 116.8 GPa, in which the direct band structure transforms to an indirect band structure. According to the electronic structure, the optical properties are analyzed systemically under different pressure..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 616004 (2011)
PbSe/PMMA Quantum Dot-Doped Fiber Materials Fabricated by a Bulk Polymerization Method
Cheng Cheng, Wang Ruodong, and Yan Jinhua
PbSe quantum dot-doped polymethyl methacrylate (PbSe/PMMA QD) fiber material is prepared by using a bulk polymerization method. The crystallization, size and distribution of the PbSe/PMMA are investigated by transmission electron microscopy (TEM). The absorption and photoluminescence (PL) spectra of the PbSe/PMMA are aPbSe quantum dot-doped polymethyl methacrylate (PbSe/PMMA QD) fiber material is prepared by using a bulk polymerization method. The crystallization, size and distribution of the PbSe/PMMA are investigated by transmission electron microscopy (TEM). The absorption and photoluminescence (PL) spectra of the PbSe/PMMA are also observed by an ultraviolet (UV)-visible-near-infrared spectrophotometer and a fluorescence spectrometer, respectively. Results show that PbSe QD are distributed uniformly in the PMMA basement. The generated QD size increases as the reaction temperature of PbO and Se increases. Strong PL emission is observed in the experiment with full width at half maximum (FWHM) achieving in the range of 100~300 nm, and peak wavelength locating in the range of 1431~2365 nm. Depending closely on the QD size, the Stokes shift of 15~72 nm is observed between the absorption peak and PL peak..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 616005 (2011)
Medical Optics and Biotechnology
Analysis of Frequency-Modulated Continuous-Wave Lidar Technique for Non-Invasive Blood Glucose Measurement
Xiong Bing, Wei Wenxiong, and He Jianjun
Continuous non-invasive glucose monitoring makes the treatment and management of diabetic disease convenient. A non-invasive technique based on the frequency-modulated continuous-wave (FMCW) lidar technique that detects the scattering coefficient of the tissue is proposed. Compared with the traditional glucose measuremContinuous non-invasive glucose monitoring makes the treatment and management of diabetic disease convenient. A non-invasive technique based on the frequency-modulated continuous-wave (FMCW) lidar technique that detects the scattering coefficient of the tissue is proposed. Compared with the traditional glucose measurement method based on optical coherence tomography, the FMCW lidar system has the advantages of simple and compact structure without moving parts, and is easy to realize portable apparatus. It mainly consists of a near-infrared semiconductor tunable laser and a detector, using heterodyne technique to convert the signal from time domain to frequency domain. A mathematical model of the system of sawtooth-wave modulation is established. Factors that affect system resolution are analyzed. Monte Carlo simulations have been performed on the tissue phantoms to investigate the slope of the system signal spectrum under different glucose concentrations. The simulations show that the system signal slope decreases 35% with a glucose concentration increment of 20 mmol/L, which agrees well with the scattering coefficients calculated by Mie theory. Proof-of-principle simulations and the experiments suggest that the FMCW method has a great potential as a convenient tool for non-invasive glucose measurement..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 617001 (2011)
Microscopy
Design of the Super-Resolution Pupil Filter in the Confocal System
Wang Mei, Yun Maojin, Liu Liren, Kong Weijin, Liang Jian, Liu Meiling, and Xia Feng
In order to improve the resolution of confocal scanning microscope system, three-zone annular binary pure phase filter is designed with the vector diffraction theory. When the high numerical aperture focused 1.4, the light intensity distribution near the focus is numerical simulated. Based on the Strehl ratio and axialIn order to improve the resolution of confocal scanning microscope system, three-zone annular binary pure phase filter is designed with the vector diffraction theory. When the high numerical aperture focused 1.4, the light intensity distribution near the focus is numerical simulated. Based on the Strehl ratio and axial resolution, the structures of the three-zone annular binary pure phase filter which achieved optical superresolution could obtained with the optimal search algorithm. The simulation results show that axial superresolution and low side-lobes can be realized with the designed three-zone annular binary phase filter in the confocal scanning microscope systems and other high numerical aperture system..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 618001 (2011)
Near UV-Band Frequency Division Multiplexing Detecting Technique with Fluorescence Microscopy
Zhang Yunbo, Zheng Jihong, Jiang Yanmeng, Hou Wenmei, Zhang Renjie, and Zhuang Songlin
The principles of the microscopic fluorescence detection with frequency division multiplexing paralleling detection technology (FDMPD) is analysed. In the FDMPD system, the exciting laser beam is firstly divided into the multi-beams, and each beam is modulated with the individual carrying frequencies. The multi-beams eThe principles of the microscopic fluorescence detection with frequency division multiplexing paralleling detection technology (FDMPD) is analysed. In the FDMPD system, the exciting laser beam is firstly divided into the multi-beams, and each beam is modulated with the individual carrying frequencies. The multi-beams exciting laser is focused on the surface of target cells to generate the multichannel fluorescent signals with corresponding carrying frequencies. Photomultiplier tube collected the fluorescent signals and transmitted the signal into the computer. Then individual channel fluorescent signal which varies with the time can be demodulated in a parallel and a high-resolution way. Employing 405 nm exciting laser sources, the two channel FDMPD system is constructed. The experiments explored micro-morphology of mouse nerve cells sample and demodulated the two channel fluorescence curves varying with the time. Furthermore, the basic parameters including the magnification, time resolution ability etc are analyzed, and the basic conditions to avoid the cross talk among multiply channels are also put forward..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 618002 (2011)
Nonlinear Optics
Incoherently Coupled Bright-Dark Soliton Pairs and Their Propagation Properties in Unbiased Photovoltaic Crystals
Peng Xiaolan, Zhou Yamin, and Wang Hongcheng
A theory is presented to investigate the existence of incoherently coupled bright-dark photovoltaic soliton pairs in an unbiased photovoltaic crystal with uniform illumination. It is found that with the same photovoltaic photorefractive effect, the two optical beams with the same polarization and wavelength but which aA theory is presented to investigate the existence of incoherently coupled bright-dark photovoltaic soliton pairs in an unbiased photovoltaic crystal with uniform illumination. It is found that with the same photovoltaic photorefractive effect, the two optical beams with the same polarization and wavelength but which are mutually incoherent can form incoherently coupled bright-dark photovoltaic soliton pairs. The expression forms of optical field and the full-width at half-maximum (FWHM) of the bright and dark components are deduced. Taking CuKNSBN for example, the variation relations between the intensity profile and FWHM and the soliton intensity is discussed. The investigation results show that when incoherently coupled bright-dark soliton pairs form, the FWHM of the dark soliton is smaller than that of the bright soliton. Therefore, it contributes little to the refractive-index change. The propagation properties are also investigated by numerical method. It is found that incoherently coupled bright-dark photovoltaic soliton pairs can propagate stably in photovoltaic crystals. When the dark soliton beam is absent, the bright soliton can still propagate in the crystal with breathing shape. When the bright soliton beam is absent, however, the dark soliton beam collapses quickly..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 619001 (2011)
OPTICAL DATA STORAGE
Traditional and Differential Readout Technology for Super-Resolution Near-Field Structure Disc
Hu Wenhua, Chang Shengli, Yang Jiankun, Li Xiujian, and Tan Jichun
Based on the established simple model of an optical system, the traditional readout signal of super-resolution near-field structure (Super-RENS) disc is simulated according to scalar diffraction theory and angular spectrum method. By comparing simulation results with experimental signals, the validity of the calculatioBased on the established simple model of an optical system, the traditional readout signal of super-resolution near-field structure (Super-RENS) disc is simulated according to scalar diffraction theory and angular spectrum method. By comparing simulation results with experimental signals, the validity of the calculation method is proved. Moreover, the differential signal, which is the difference of signals read out by high and low power incident laser, is simulated for single track and three tracks recording pattern. It is shown that, by using the differential readout method, the cross talk from adjacent pits is decreased and high quality readout signal can be obtained..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 621001 (2011)
Optical Design and Fabrication
New Type of Bessel-Like Amplatitude Modulation Spiral Phase Plate
Wang Jingang, Bu Jing, Wang Mingwei, and Yuan Xiaocong
A new kind of phase plate using a variable Bessel-like function is designed and fabricated. The amplitude part is the variable Bessel-like function and the phase part is the spiral phase plate. The design suppresses the beam′s sidelobes significantly by choosing a proper modulatd parameter. A pure phase plate can be goA new kind of phase plate using a variable Bessel-like function is designed and fabricated. The amplitude part is the variable Bessel-like function and the phase part is the spiral phase plate. The design suppresses the beam′s sidelobes significantly by choosing a proper modulatd parameter. A pure phase plate can be gotten through an encoding method. After optimization of gray scale laser direct writing process, the new kind of phase plate is fabricated on the photoresist slide substrate. Performance of the modulated phase plate is verified by using beam intensity distribution, which is in excellent agreement with the theoretical prediction. The proposed method gives rise to a simple, reliable, and low-cost micro-optical element solution for the generation of high quality optical vortices..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 622001 (2011)
Optimization Design of Partially Compensating Lens Based on Zemax
Meng Xiaochen, Hao Qun, Zhu Qiudong, and Hu Yao
Optimization design of partially compensating lens is one of the key problems for aspheric surface testing using partially compensating lens. A design method for the partially compensating lens based on Zemax, which takes the slope of wave-front as the optimization objective, is proposed. First the relation among residOptimization design of partially compensating lens is one of the key problems for aspheric surface testing using partially compensating lens. A design method for the partially compensating lens based on Zemax, which takes the slope of wave-front as the optimization objective, is proposed. First the relation among residual wave-front slope, and interference fringe density and dispersive spot are analyzed, leading to the conclusion that the dispersive spot can quantitatively characterize the residual wave-front slope and its radius is taken as the optimization target. Then the method is applied to the optimization design of partially compensating lenses corresponding to three kinds of aspheric surfaces. The results indicate that, on the precondition that the interference fringes are detectable, the method can help complete the optimization design of partially compensating lens more simply, faster and more visually, resulting in decrease of the residual wave-front slope and reduction in the interference fringes density. Therefore, the measurement range of the interferometer for testing aspheric surface is expanded, and aspheric surfaces with higher spatial frequency can still be measured without increasing the resolution of interferogram detector..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 622002 (2011)
Optical Design of Aerial Digital Camera Based on Large Planar Array CCD
Yan Aqi, Yang Jianfeng, and Cao Jianzhong
Optical system of an aerial digital camera based on large planar array CCD with 50 million pixels is designed, considering aerospace environment and imaging quality. The focal length of aerial digital camera is 75 mm, F number is 4，and distortion is less than 0.1%. The required working temperature is between -40 ℃～60 ℃Optical system of an aerial digital camera based on large planar array CCD with 50 million pixels is designed, considering aerospace environment and imaging quality. The focal length of aerial digital camera is 75 mm, F number is 4，and distortion is less than 0.1%. The required working temperature is between -40 ℃～60 ℃. After carefully research on the influence of temperature on imaging quality of optical system, a new approach is put forward. Aerial digital camera can reach excellent imaging quality when soaking in a large temperature change by this new technique. This approach can not only eliminate defocusing effect of optical system caused by temperature change, but also make the aerial digital camera be smaller and less weighty..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 622003 (2011)
Design of Telecentric Off-Axis Three-Mirror System of Imaging Spectrometer with Wide Field-of-View
Liu Xiaomei, and Xiang Yang
In order to meet the needs of the wide field-of-view (FOV) imaging spectrometer development, the problem about optical design of telecentric, wide FOV, large relative aperture, off-axis three-mirror system is studied, and the expressions of initial configuration parameters and the third-order aberrations for flat fieldIn order to meet the needs of the wide field-of-view (FOV) imaging spectrometer development, the problem about optical design of telecentric, wide FOV, large relative aperture, off-axis three-mirror system is studied, and the expressions of initial configuration parameters and the third-order aberrations for flat field, telecentric, three-mirror system are educed. With the specific requirements of 0.4~2.5 μm spectral range, F number is 4, 720 mm focal length, 10° FOV, a flat field, telecentric, off-axis three-mirror imaging system is designed, in which the secondary mirror is convex spheric mirror, the primary mirror and the third mirror are concave conicoid and coplanar, and all the three mirrors are coaxial. The design result indicates that the imaging quality of the designed system approaches the diffraction limit at full FOV in the required wave band..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 622004 (2011)
Innovated Lens Design for Catadioptric Zoom System
Xu Weicai, and Huang Wei
A new lens designed for the long focal length, catadioptric zoom telescope is presented. By setting the variable diaphragm near the primary mirror, there is no necessity to use a floating variable diaphragm in the zoom part. Then using the re-imaging form and field lens, the zoom part only contains variator and compensA new lens designed for the long focal length, catadioptric zoom telescope is presented. By setting the variable diaphragm near the primary mirror, there is no necessity to use a floating variable diaphragm in the zoom part. Then using the re-imaging form and field lens, the zoom part only contains variator and compensator, without focus unit and primelens as usual and there is no unusual partial dispersion glass used for the correction of secondary spectrum, so the complexity of zoom part is greatly reduced. By using this new lens form, a catadioptric zoom telescope working in the visible wavelength band with variable focal length between 600 and 3000 mm, 300 mm maximum aperture is designed and then optimized. The modulation transfer function (MTF) of this optimized lens is greater than 0.3 at 60 lp/mm across all the focal lengths and field of view. The result indicates that this lens reaches good image quality and is cost-effective for manufacture, so this new lens is very suitable for the long focal length, visible zoom imaging system..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 622005 (2011)
Study of Indoor concentration Test System
Zhao Huifu, Liu Hua, Jing Lei, Wang Yao, Xu Wenbin, and Lu Zhenwu
Because of the large divergence angle and small test caliber, the solar simulator is not suitable for the test of photovoltaic concentration system. In order to make up this weakness, an indoor concentration test system with a large caliber and a high parallelism is designed. A new concentration test method——discrete sBecause of the large divergence angle and small test caliber, the solar simulator is not suitable for the test of photovoltaic concentration system. In order to make up this weakness, an indoor concentration test system with a large caliber and a high parallelism is designed. A new concentration test method——discrete spectral local measurement method——is proposed. Firstly, two-stage Fresnel concentration system is chosen as a test object and monochromatic light local measurement method is used to test its concentration efficiency. Then the average concentration efficiency is calculated according to the weight and concentration efficiency of monochromatic light. Finally, the experimental results are compared with the simulated results. The simulated concentration efficiency is 88.623%, and the measured concentration efficiency is 85.45%, with the difference of 3.173%. The transmittance and the uniformity of concentration spot are quite close. The difference of concentration efficiency mainly come from manufacturing error and measuring error. The scientificity and feasibility of the indoor concentration test system are confirmed through the experimental data analysis. The light divergence angle of indoor concentration test system is 0.267°, which can match sunlight divergence angle, and its 145 mm caliber can test the performance of concentration system with the large caliber. Indoor concentration test system with simple structure and low cost will have broad application prospects in solar-energy concentration field..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 622006 (2011)
Optical Devices
Defect-Mode Properties of Photonic Crystals Constructed with a Portion of Photonic Quasicrystals
Shen Yun, Yu Guoping, Fu Jiwu, Zou Liner, and Fan Dinghuan
Complex two-dimensional (2D) photonic crystal (PC) constructed with a portion of 12-fold photonic quasicrystals (PQ) is proposed and its defect-mode properties are studied by performing finite-difference time-domain (FDTD). The results show that such complex PC allow for richer defect modes and higher degree of flexibiComplex two-dimensional (2D) photonic crystal (PC) constructed with a portion of 12-fold photonic quasicrystals (PQ) is proposed and its defect-mode properties are studied by performing finite-difference time-domain (FDTD). The results show that such complex PC allow for richer defect modes and higher degree of flexibility compared with conventional periodic PCs due to the absence of translational symmetry in the portion of 12-fold PQ. It is also demonstrated that the frequencies of defect modes are related to the strength of the interplay of the removed cylinders. The defect modes of flexibility and tunability can be obtained by combining different defect cavities..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 623001 (2011)
Design and Analysis of Multi-Layer Diffractive Optical Elements with Cauchy Dispersion Formula
Xue Changxi, Cui Qingfeng, Yang Liangliang, and Liu Tao
According to the theory of phase retardation expression, the relation between the phase retardation function of multi-layer diffractive optical element (MLDOE) with Cauchy dispersion approximate refractive indices formula and characteristics of material, along with the relation between diffraction efficiency and designAccording to the theory of phase retardation expression, the relation between the phase retardation function of multi-layer diffractive optical element (MLDOE) with Cauchy dispersion approximate refractive indices formula and characteristics of material, along with the relation between diffraction efficiency and design wavelengths are studied. In the visible region from 400 to 700 nm, the MLDOE consists of two harmonic diffractive elements with different dispersive optical materials such as polymethyl methacrylate and polycarbonate. The maximum bandwidth integrated average diffraction efficiency (BIADE) of the MLDOE designed with Cauchy dispersion approximate refractive indices formula is 99.62%, and the corresponding design wavelengths are 440.5 nm and 605.5 nm. The diffraction efficiency of BIADE and of MLDOE is analyzed with design wavelengths of thispaper and other methods. Distribution error of diffraction efficiencies is given, which proves that the diffraction efficiencies of MLDOE are independent on materials but dependent on design wavelengths only..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 623002 (2011)
Physical Optics
Transmission and Polarization Properties of Circular-Birefringence Fiber Gratings and Their Applications in Magnetic-Field Sensor
Su Yang, Zhu Yong, Yi Xiaoxin, and Li Yuquan
The transmission and polarization properties of circular birefringence fiber gratings are analyzed. Based on the Jones matrix and the coordinate conversion, the evolutions with wavelength of transmission spectrum and the polarization properties of output light with different magnetic field intensities, grating lengths The transmission and polarization properties of circular birefringence fiber gratings are analyzed. Based on the Jones matrix and the coordinate conversion, the evolutions with wavelength of transmission spectrum and the polarization properties of output light with different magnetic field intensities, grating lengths and incident states of polarization (SOP) are analyzed. The results show that circular birefringence leads to the splitting of transmission spectrum and variation of transmitted SOP for different wavelengths. It is demonstrated that the polarization-dependent loss (PDL) and the third Stocks parameter increase monotonously with applied magnetic field, and they can be used in magnetic field sensor. The measurement range and sensitivity are dependent on the grating structure and material. The dynamic measurement range of Bi-YIG and YIG fiber gratings are both given..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 626001 (2011)
Fast Simulation and Interference Properties of Photons Transmission in Turbid Material
Lin Lin, Gao Yingjun, Jin Chongxing, Lin Huizhen, and Luo Yunhan
In order to analyze low-coherent signal characteristics of turbid material, Monte Carlo(MC) numerical model is established. The Gaussian distribution of optical intensity and coherent gate of optical source are introduced into numerical simulation. An accelerated method is introduced into simulation of coherent intensiIn order to analyze low-coherent signal characteristics of turbid material, Monte Carlo(MC) numerical model is established. The Gaussian distribution of optical intensity and coherent gate of optical source are introduced into numerical simulation. An accelerated method is introduced into simulation of coherent intensity of turbid medium. Under condition of forword scattering, anisotropy factor g=0.9, the results of scaling method match with those of MC simulation with mean relative error of 2.37%. When g decreases to 0.5, and mean relative error increases to 4.69%. In calculation of coherent signals of different depths, similar data in surface layer are gotten by the two methods. In experiment, optical signals from 0 to 1 mm depth in the mixture liqid of IntralipidTM and India ink are measured by low-coherent system and fitted by accelerated Monte-Carlo method succesfully..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 626002 (2011)
Precisely Integrated Wavefront Sensorless Calibration of High-Resolution Space Optical System with Large Position Errors
Han Xingzi, Hu Xinqi, and Yu Xin
Relative position errors among mirrors in a three-mirror reflective system can seriously degrade the performance of the whole space optical remote sensing system, so we have to calibrate these errors in orbit. A new wavefront sensorless calibrating method that integrates stochastic parallel gradient descent control algRelative position errors among mirrors in a three-mirror reflective system can seriously degrade the performance of the whole space optical remote sensing system, so we have to calibrate these errors in orbit. A new wavefront sensorless calibrating method that integrates stochastic parallel gradient descent control algorithm, phase-diversity method and sensitive matrix inversion algorithm is proposed. This method retains the high resolution of sensitive matrix inversion algorithm and largely increases the dynamic range of stochastic parallel gradient descent control algorithm. Additionally, it does not need wavefront sensors to measure the wavefront error, thus simplifies the whole system, making it more feasible. Through computer simulation of a typical high-resolution space optical system in orbit and calibration of its relative position errors of the three mirrors using this integrated method, significantly improved calibrating range and high calibration precision are demonstrated, thus the merits of the new method are proved..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 626003 (2011)
Spectroscopy
Investigations on NIR-SERS Spectra of Serum for Liver Cancer Based on NIR-SERS Substrate
Liu Renming, Liu Ruiming, Wu Yanchun, Liu Zhenquan, Zhang Deqing, Zi Xingfa, and Si Minzhen
Investigations on near infrared surface-enhanced Raman scattering (NIR-SERS) spectra of the serum for patients with liver cancer and healthy persons based on Ag nanofilms prepared by using electrostatic self-assembly are reported. Analysis indicates NIR-SERS spectra of the sera between healthy persons and liver cancer Investigations on near infrared surface-enhanced Raman scattering (NIR-SERS) spectra of the serum for patients with liver cancer and healthy persons based on Ag nanofilms prepared by using electrostatic self-assembly are reported. Analysis indicates NIR-SERS spectra of the sera between healthy persons and liver cancer patients are different. Firstly, Raman bands at 630, 720, 812 and 1578 cm-1 become weaker (even disappear) in NIR-SERS spectra of the sera for cancer liver patients but stronger in NIR-SERS spectra of the sera for healthy persons. Secondly, Raman bands at 1130 cm-1 and 1204 cm-1 in NIR-SERS spectra of the sera for healthy persons have blue shifts to 1135 cm-1 and 1269 cm-1 in NIR-SERS spectra of sera for cancer liver patients, respectively. Meanwhile, a new Raman band at 558 cm-1 appears in NIR-SERS spectra of liver cancer patients. Additionally, striking spectral differences are abvious in NIR-SERS spectra in the intensity ratios at 630/300, 1130/300, and 1578/300 cm-1. These three peak-intensity ratios of liver cancer patients with values of 0.848±0.042, 1.094±0.118, 0.914±0.070, respectively, are more notable (mean±S.D., n=15, P<0.01) compared with those of healthy persons (1.985±0.487, 1.568±0.286, 1.189±0.108, respectively). The results show that the intensity relative peak-ratios at 630/300, 1130/300, and 1578/300 cm-1 can be used to discriminate liver cancer patients from healthy persons, which indicate these three intensity ratios can be served as NIR-SERS spectral criteria for the diagnosis of cancer liver..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 630001 (2011)
Raman Spectroscopic Analysis of Carotenoids of Single Human Blood Platelets
Wang Guiwen, Peng Lixin, Shen Weidong, Tao Zhanhua, and Li Yongqing
The Raman spectra of single blood platelets from human body are acquired by using Raman tweezers and the biochemical information of Raman spectra is extracted. The carotenoids concentration of platelets is found to be highest among the blood. But the carotenoids concentration of platelets is heterogeneous and is irreleThe Raman spectra of single blood platelets from human body are acquired by using Raman tweezers and the biochemical information of Raman spectra is extracted. The carotenoids concentration of platelets is found to be highest among the blood. But the carotenoids concentration of platelets is heterogeneous and is irrelevant to the content of lipids and protein of platelets. After platelets is activated, the Raman intensities of carotenoid are constant but those of proteins arise. The Raman intensity of carotenoids decreases but the relative intensities of lipids remain stable when platelets are stored at 25 ℃. The Raman intensities of lipids stored at 4 ℃ 12 d decline while those of carotenoids unchange..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 630002 (2011)
Thin Films
Performance Analysis of Local Optimization Algorithm in Reverse Engineering of Multilayer Optical Coatings
Wu Suyong, Long Xingwu, Yang Kaiyong, and Huang Yun
An infrared antireflection (AR) coating for germanium is taken as an example to numerically analyze the performance of the local optimization algorithm which is based on Matlab optimization toolbox in the local optimal design of multilayer optical coatings and their application feasibility in the algorithm development An infrared antireflection (AR) coating for germanium is taken as an example to numerically analyze the performance of the local optimization algorithm which is based on Matlab optimization toolbox in the local optimal design of multilayer optical coatings and their application feasibility in the algorithm development of reverse engineering of multilayer optical coatings. The reasons and the solutions of the mutiple solutions in numerical experiments are discussed. The numerical optimization results show that the derivative algorithms of Matlab optimization toolbox have better local optimum point search ability and converging speed than reference methods. While the performance of non-derivative algorithms is poor but might be applicable in the initial local design stage to explore more search directions. In the reverse engineering of multilayer optical coatings, the algorithm lsqnonlin and fsolve are excellent in inversion which determines the quality of optical structural parameters. They are recommended to be the main reverse engineering algorithms. The fminunc and fmincon algorithms can be chosen as supplementary reverse engineering algorithms for their acceptable reverse determination effectiveness. The fminimax and other non-derivative algorithms are poor in effectiveness and stochastic in final solutions, which can easily converge to wrong structural parameters and could not be used as reverse engineering algorithms..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 631001 (2011)
Analysis of Light Out-Coupling Efficiency in Top-Emitting Polymer Light-Emitting Devices
Gui Yuchang, Wen Shangsheng, Zhang Jianping, Wang Baozheng, and Zhao Baofeng
The light out-coupling efficiency of top-emitting polymer light-emitting devices (TEPLED) based on poly ［2-me-thoxy-5-(2-ethyl-hexyloxy)-1, 4-phenylenevinylene］ (MEH-PPV) is simulated by applying the transfer matrix method and software Matlab. The influence of anode materials, cathode materials, capping layers and obseThe light out-coupling efficiency of top-emitting polymer light-emitting devices (TEPLED) based on poly ［2-me-thoxy-5-(2-ethyl-hexyloxy)-1, 4-phenylenevinylene］ (MEH-PPV) is simulated by applying the transfer matrix method and software Matlab. The influence of anode materials, cathode materials, capping layers and observing angle on the performance of the TEPLED′s out-coupling efficiency is studied. When compared with Ag film anode device, the one based on distributed Bragg reflector (DBR) presents higher out-coupling efficiency, reaching 47.43%. To decrease the light absorption and reflection by sub-transparent metal, transparent materials cathode is designed so that the light-coupling efficiency raises about 10% compared with Ag anode devices, reaches 67.11%. The influence of DBR on the observing angles of total TEPLED is studied. The results show that it has little effect on light-coupling efficiency of TEPLED by DBR when the observing angle changes in a narrow range (30°). It has more effect on light-coupling efficiency when the observing angle is more than 30°. The application of DBR provides a theoretical basis for the optimization of out-coupling efficiency of TEPLED..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 6, 631002 (2011)
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