Contents
2013
Volume: 33 Issue 2
48 Article(s)
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Atmospheric Optics and Oceanic Optics
Numerical Simulation of Return Photons Number of Sodium Laser Beacon in the Atmospheric Turbulence
Liu Xiangyuan, Qian Xianmei, Cui Chaolong, and Rao Ruizhong
For laser of the long pulses, short pulses and continuous wave with circular polarization, the effect of atmospheric turbulence on the return photons number of sodium laser beacon is studied by numerical simulation method of light propagation under the Greenwood and Hufnagel-valley5/7 (HV5/7) model for atmospheric turbFor laser of the long pulses, short pulses and continuous wave with circular polarization, the effect of atmospheric turbulence on the return photons number of sodium laser beacon is studied by numerical simulation method of light propagation under the Greenwood and Hufnagel-valley5/7 (HV5/7) model for atmospheric turbulence. Results indicate that compared with Greenwood model under the HV4/7 model, the atmospheric turbulence causes the further dispersive distribution of laser intensity in the mesosphere and the reduced peak intensity, and return photons number is increased for laser of long pulses and continuous wave with circular polarization. However, the circularly-polarized short pulses cannot get more return photons under the HV5/7 model for atmospheric turbulence. Furthermore, the distribution of photons number exited by the circularly-polarized short pulses and continuous-wave laser is in an agreement with the distribution of laser intensity, but the long pulses are in absence of this character..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 201001 (2013)
Atomic and Molecular Physics
Dependence of Strong-Field Double Ionization of Xenon Atoms by Elliptically Polarized Laer Pulses on Carrier-Envelope Phase
Yu Benhai, and Li Yingbin
With the classical ensemble model, carrier envelope phase (CEP), which is dependent strong-field double ionization (DI) of xenon atoms by elliptically polarized laser pulses, is investigated. The results show that the momentum distributions of Xe2+ ion strongly depend on CEP. Sequential double ionization (SDI) and nonsWith the classical ensemble model, carrier envelope phase (CEP), which is dependent strong-field double ionization (DI) of xenon atoms by elliptically polarized laser pulses, is investigated. The results show that the momentum distributions of Xe2+ ion strongly depend on CEP. Sequential double ionization (SDI) and nonsequential double ionization (NSDI) of final state exist simultaneously in DI events with this laser field. The yield of SDI decreases firstly, then increases as CEP increases. But the yield of NSDI increases firstly, then decreases as CEP increases. The yields of SDI and NSDI both show a periodic change, and the period is π. Analysis of trajectories shows that the events of NSDI occur still via recollision, and this process can be interpreted well through the three-step model. In addition, the ionization time of two electrons in SDI and the recollision time in NSDI strongly depend on CEP which leads the final-state momentum distribution of Xe2+ ion changes with CEP..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 202001 (2013)
Diffraction and Gratings
Effects of Incoherent Monochromatic LED Light Source on Formation of Bessel Beam
Fang Xiang, Wu Fengtie, and Cheng Zhiming
Based on the theory of partially coherent light, this article studies the influence of the spatial coherence of incoherent monochromatic LED light source on the generation of Bessel beam. When the partially coherent light goes through an axicon, higher-order Bessel functions appear in the light intensity distribution, Based on the theory of partially coherent light, this article studies the influence of the spatial coherence of incoherent monochromatic LED light source on the generation of Bessel beam. When the partially coherent light goes through an axicon, higher-order Bessel functions appear in the light intensity distribution, and the light intensity is the linear superposition of each-order Bessel functions. Light intensity distributions are numerically simulated. The result shows that the shorter initial coherent length is, the greater the effect of high-order derivatives is, and more obvious the difference between Bessel beam and the ideal Bessel is, and that the light intensity is non-zero in dark rings and section of light distributions is fuzzier. Through an experimental setup that can regulate initial coherent length of light, nearly ideal Bessel beam is generated. The experimental results agree with theoretical analysis..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 205001 (2013)
Fiber Optics and Optical Communications
Wavelength Division Multiplexing Subnet Partition Based on Clustering Algorithm in Multidimensional Space
Ren Yu, Qiu Kun, Ling Yun, and Huang Jin
Wavelength division multiplexing (WDM) optical network is the direction of the airborne network development. The combination of wavelength routing and electric exchange is the main method to complete the airborne WDM optical network interconnection currently. One of the cruxes is how the airborne network node is subnetWavelength division multiplexing (WDM) optical network is the direction of the airborne network development. The combination of wavelength routing and electric exchange is the main method to complete the airborne WDM optical network interconnection currently. One of the cruxes is how the airborne network node is subnetted. The large traffic distribution of mutual communication between the nodes is assigned to the same subnet, employing the wavelength routing transmission; the low traffic distribution of mutual communication between the nodes is interconnected by electric exchange. Based on clustering algorithm in multidimensional space, the node traffic distribution problem is converted into spatial clustering problem, which completes node location preprocessing and node flux-location clustering to solve the airborne WDM network subnet partition, and it finally verifies the feasibility of the method through examples..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 206001 (2013)
Improved 60 GHz Millimeter-Wave Generator Based on Feed-Forward Modulation
Xu Lili, Ning Tigang, Li Jing, Pei Li, You Haidong, Chen Hongyao, and Zhang Chan
A radio over fiber (ROF) system is a product of the broad band and wireless in the communication industry. It combines the optical fiber communication technology and millimeter-wave communication technology, and has a broad application prospect. At present many countries mark off unlicensed continuous-frequency spectraA radio over fiber (ROF) system is a product of the broad band and wireless in the communication industry. It combines the optical fiber communication technology and millimeter-wave communication technology, and has a broad application prospect. At present many countries mark off unlicensed continuous-frequency spectra in 60 GHz millimeter wave frequency band, which makes 60 GHz millimeter-wave wireless communication become one of the hot researches in the field of close wireless communication. In order to reduce the cost of a ROF system and improve its performance, an improved 60 GHz millimeter-wave generator based on feed-forward modulation (FFM) technique is proposed. The principle of the photoelectric device is analysed and the effect of different parameters setting in the performance of the system curve is simulated. The scheme combines with the advantages of forward modulation technology and light wavelength division multiplexing technology. It simplifies the complexity of the system, reduces the cost of the ROF system, reduces the error rate and improves the performance of the whole system..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 206002 (2013)
Suppression on Fiber Stimulated Brillouin Scattering Based on Phase Modulation
Xie Shuping, and Xu Guoliang
The phase modulator is used to increase the threshold of the stimulated Brillouin scattering. Effects of modulation depth and frequency on the threshold are analyzed. The increase of the threshold is determined by the modulation depth which is related to the half-wave voltage. A heterodyne method to measure the half-waThe phase modulator is used to increase the threshold of the stimulated Brillouin scattering. Effects of modulation depth and frequency on the threshold are analyzed. The increase of the threshold is determined by the modulation depth which is related to the half-wave voltage. A heterodyne method to measure the half-wave voltage of the phase modulator is proposed in order to determine the modulation depth. The results of the experiments demonstrate that the half-wave voltage is 3.7 V when modulation frequency is 50 MHz. The variation of the stimulated Brillouin scattering threshold are researched through experiments when the modulation frequency is 50 MHz and modulation depth is 1.435 and 2.631. Results show that the threshold increases 6.7 dB when modulation depth is 2.631, which matches the theoretic calculation. High threshold is obtained with low power and low modulation frequency..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 206003 (2013)
Differential Space Time Code for Free Space Optical Multiple Input Multiple Output System
Chen Juan, Ke Xizheng, and Cheng Ting
Laser is always affected by atmospheric turbulence in atmosphere transmission, and channel estimation will become more difficult at poor atmospheric condition. According to Chadi Abou-Rjeily′s coding idea, introducing permutation matrix instead of negative form of symbols in the real area Alamouti method, utilizing binLaser is always affected by atmospheric turbulence in atmosphere transmission, and channel estimation will become more difficult at poor atmospheric condition. According to Chadi Abou-Rjeily′s coding idea, introducing permutation matrix instead of negative form of symbols in the real area Alamouti method, utilizing binary pulse position modulation, a differential space-time code scheme that does not require channel estimates for free space optical communication is proposed. The simulation results show that, compared with Alamouti coding which requires channel estimates, this method can obtain the same diversity gain. At the same time, it is relatively simple and more feasible in practice..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 206004 (2013)
Tunable Liquid-Core Optical Filter Based on Multimode Interference
Zhang Yanjun, Xu Huabin, Xie Xiaopeng, and Liu Shuangzhu
A tunable reflection type band-rejection optical filter based on capillary filled with liquid instead of multimode fiber is projected. The active component of the structure of filtering is a segment of capillary filling liquid and Hg. One end of the capillary is docked co-axial with a single-mode fiber and the other enA tunable reflection type band-rejection optical filter based on capillary filled with liquid instead of multimode fiber is projected. The active component of the structure of filtering is a segment of capillary filling liquid and Hg. One end of the capillary is docked co-axial with a single-mode fiber and the other end is sealed with hot melt adhesive. Refractive index of liquid is greater than the capillary refractive index and the capillary core diameter is larger, so there is equivalent to the formation of a large core diameter multimode fiber. On the basis of the multi-mode interference principle, because the capillary liquid core is sensitive to the temperature, the tunable optical filtering is achieved. Simulation and experiment confirm the feasibility of the theory. The filter has some advantages, such as simple structure, low cost and so on, for which insertion loss is 5.12 dB, 3 dB bandwidth is 3.3 nm and the filtering range is up to 7 nm..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 206005 (2013)
Preparation and Birefringence Properties of the Embedded Multi-Core Hollow Fiber
Zhao Enming, Yuan Libo, Tian Fengjun, and Yang Yuanyuan
An embedded multi-core hollow high birefringence fiber is designed and fabricated. Since the structure of the optical fiber core and the cladding is geometric asymmetric, it has high birefringence characteristic which can be used to overcome the problems of the polarization-induced fading of the fiber integrated interfAn embedded multi-core hollow high birefringence fiber is designed and fabricated. Since the structure of the optical fiber core and the cladding is geometric asymmetric, it has high birefringence characteristic which can be used to overcome the problems of the polarization-induced fading of the fiber integrated interferometer. Using the finite element method to analyze the mode birefringence changes in different sizes, it can be concluded that increasing the length of the major axis of the core, or reducing the thickness of the inner cladding can effectively improve the birefringence. And the mode birefringence of 1.42×10-4 at 1310 nm is obtained. Experimental and analytical results show that the embedded multi-core hollow high birefringence fiber has a certain potential in in-fiber integrated interferometers for reducing polarization-induced fading and can be used to manufacture in-fiber integrated interferometer with polarization-maintaining function..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 206006 (2013)
Effect of Beam Characteristic on Detection Efficiency for the Coherent Optical Detection System Based on Acousto-Optic Deflection
He Ning, and Xie Zhaoling
In coherent detection system, the matching of signal beam and local oscillator and the beam characteristic have important effects on the detection efficiency. The light-intensity distributions of Gaussian beam and flattop beam are simulated in Matlab respectively, and the mathematical feature of the two spots are proviIn coherent detection system, the matching of signal beam and local oscillator and the beam characteristic have important effects on the detection efficiency. The light-intensity distributions of Gaussian beam and flattop beam are simulated in Matlab respectively, and the mathematical feature of the two spots are provided. Based on the acousto-optic deflection effect, the effect of spot size matching and signal beam parallel moving along light axis on the coherent detection efficiency is analyzed by building overlay model between Gaussian beam and rectangle beam. The results show that, with the assurance of beam collimation and equivalence in the total energy of two spots, we can get the optimal overlapping efficiency of 79.6% when the energy density of rectangle spot is 0.8 times as the central energy density of Gaussian spot. The non-collimation of the beams will reduce the detection efficiency when the signal beam is mixed with the local-oscillator beam on the optoelectronic sensor surface. But while rectangle beam is mixed with Gaussian beam, the variation of detection efficiency tends to become gentle when beams deviate from optic axis within ±0.5 mm..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 206007 (2013)
Geometric Optics
Effect of Jones Matrix Elements on the Polarization Aberrations in Schmidt Prism
Lu Jinjun, Zhu Weibing, and Sun Xueping
To study the relationship between the characteristic parameters of the Schmidt prism and the polarization aberration, the diffraction integrals obtained from the polarization and the diffraction effect of the Schmidt prism are analyzed. The four key parameters that affect the polarization aberration are determined. TheTo study the relationship between the characteristic parameters of the Schmidt prism and the polarization aberration, the diffraction integrals obtained from the polarization and the diffraction effect of the Schmidt prism are analyzed. The four key parameters that affect the polarization aberration are determined. The conditions required to the calibration of the Schmidt prism polarization aberration are also obtained. In the experiment, Jones matrix method of Schmidt prism is adopted to measure the three different Jones matrixes. The polarization aberration of Schmidt prism is completely eliminated under the condition that b=0. Experimental results show that the described theoretical analyses are correct..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 208001 (2013)
Holography
Digital Holographic Detection of Optical Matrix Elements in Optical System
Li Junchang, Lou Yuli, Gui Jinbin, Yuan Caojin, and Song Qinghe
According to the theory of matrix optics, axisymmetric paraxial optical system can be described by 2×2 matrix and it is necessary to get the accurate optical parameters and geometric location information of all components when determining the optical system matrix of optical system. A new method to determine opticAccording to the theory of matrix optics, axisymmetric paraxial optical system can be described by 2×2 matrix and it is necessary to get the accurate optical parameters and geometric location information of all components when determining the optical system matrix of optical system. A new method to determine optical matrix elements of system using digital holographic experiment is put forword, free from knowing the relevant parameters of the system element. Furthermore, experimental evidence of detection method is given. The experimental study show that the matrix elements can be obtained accurately with method, which has practical significance for applications of matrix optics..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 209001 (2013)
Imaging Systems
Study on the Passive Terahertz Image Target Detection
Zhang Xin, Zhao Yuanmeng, Deng Chao, and Zhang Cunlin
A target detection method for passive terahertz images is put forward. Original 0.22 THz images are captured using pre-developed passive scan imaging system. The original images are de-noised by spatial filtering. Then the point spread function of the imaging system is measured through pinhole images analysis, and is aA target detection method for passive terahertz images is put forward. Original 0.22 THz images are captured using pre-developed passive scan imaging system. The original images are de-noised by spatial filtering. Then the point spread function of the imaging system is measured through pinhole images analysis, and is applied to reconstruct the images with the Lucy-Richardson iterative algorithm. Finally, gray level transform and edge detection are adopted to improve the images′ contrast and resolution capability. Experimental results show that the proposed method is able to effectively improve passive terahertz images′ quality and enhance the imaging system′s ability of detecting hidden suspicious objects..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 211002 (2013)
Instrumentation, Measurement and Metrology
Effect of Spectral-Line Shift on Radiometric Measurement Accuracy of Spaceborne Imaging Spectrometer
Zhang Junqiang, Yan Changxiang, and Xin Jiuyuan
The effect of spectral-line shift on radiometric measurement accuracy of spaceborne imaging spectrometer during laboratory radiometric calibration, onboard radiometric calibration and onboard radiometric measurement is analyzed. Radiometric transmission model from laboratory radiometric calibration to onboard radiometrThe effect of spectral-line shift on radiometric measurement accuracy of spaceborne imaging spectrometer during laboratory radiometric calibration, onboard radiometric calibration and onboard radiometric measurement is analyzed. Radiometric transmission model from laboratory radiometric calibration to onboard radiometric measurement has been established, and relationship between the uncertainty of radiometric measurement on entrance pupil and spectral-line shift is simulated. Results show that radiometric measurement error is linear to spectral-line shift and radiance distribution gradient on entrance pupil of imaging spectrometer. The radiometric measurement error caused by spectral width deviation is one order of magnitude larger than that caused by central wavelength deviation. For a typical imaging spectrometer [10 nm spectral width in visible near infrared spectroscopy (VNIR) band and 20 nm in shortwave infrared (SWIR) band], central wavelength deviation is less than 2 nm and spectral width deviation is less than 0.1 nm in VNIR band, or central wavelength deviation is less than 3 nm and spectral width deviation is less than 0.1 nm in SWIR band, which is necessary to ensure the uncertainty of radiometric measurement caused by spectral line-shift less than 6% and absolute accuracy of radiometric measurement on entrance pupil is superior to 10%..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 212001 (2013)
In-Place Calibration of Stokes Ellipsometer′s Instrument Matrix
Zhang Yong, Huang Zuohua, Zhao Zhentang, Zeng Xianyou, and Zhou Jinzhao
Stokes ellipsometer can measure the optical parameters of thin films rapidly. The precision of the instrument matrix of Stokes ellipsometer directly affects the measurement of the Stokes parameters of the light reflected by films and indirectly limits the measurement accuracy of the optical parameters of films. It is sStokes ellipsometer can measure the optical parameters of thin films rapidly. The precision of the instrument matrix of Stokes ellipsometer directly affects the measurement of the Stokes parameters of the light reflected by films and indirectly limits the measurement accuracy of the optical parameters of films. It is studied that how to generate elliptically polarized light with a combination of linearly polarized light and standard films theoretically. According to the four-point calibration method, the instrument matrix with combination of linearly polarized light and standard films in place are calculated, and the errors caused by the azimuth of optical components and its defects in traditional calibration methods are avoided effectively, thereby improving measurement accuracy of the optical parameters of thin films. The experimental results show that, in the method, the deviation of the measurement of Stokes parameters of light reflected by the film is less than 0.6% and the measurement deviations of thickness and refractive index are less than 0.2 nm, 0.003 repectively..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 212002 (2013)
Application of Imaging VISAR to Pre-Heating Experiment of Au Conical Target for Fast Ignition
Xu Tao, Wei Huiyue, Wang Feng, Peng Xiaoshi, Shan Lianqiang, and Liu Shenye
The application of the imaging VISAR to the pre-heating experiment of Au conical target for fast ignition is proposed. The pre-heating experiments using different kinds of Au cones which have the diverse thicknesses of 5 μm and 10 μm are studied. The experimental data show that the velocity of the two kinds of cone areThe application of the imaging VISAR to the pre-heating experiment of Au conical target for fast ignition is proposed. The pre-heating experiments using different kinds of Au cones which have the diverse thicknesses of 5 μm and 10 μm are studied. The experimental data show that the velocity of the two kinds of cone are 2.2 km/s and 0.6 km/s. Details of the pre-heating physical progress are described, which indicate that the Au cone having thickness of 10 μm is less affected by the pre-heating effect. The experimental results show that the imaging VISAR has the ability to measure the low velocity of free surface, and the whole facility is effective for further experiment..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 212003 (2013)
Method of Measurement on Time-Interval in Pulsed Laser Ranging
Chen Ruiqiang, and Jiang Yuesong
The performance of pulsed laser ranging is directly influenced by the method how to measure the time-interval. Refer to the idea of interpolation time-interval measurement, the character of triangle reference signal is used to realize measurement on time-interval which has advantages of long measurement range and high The performance of pulsed laser ranging is directly influenced by the method how to measure the time-interval. Refer to the idea of interpolation time-interval measurement, the character of triangle reference signal is used to realize measurement on time-interval which has advantages of long measurement range and high precision. The principle how to use triangle reference signal to realize measurement on time-interval is described. The factors that affect the precision of time-interval measurement is quantitatively analyzed. It is pointed out that the frequency of triangle reference signal and the noise attached in triangle reference signal are the two main factors which affect the precision of time-interval measurement. Then, their affect on the precision of time-interval measurement is numerically simulated. A confirmatory experiment is designed to explain how the noise attached in triangle reference signal affects the precision of time-interval measurement. Both the numerical simulation and the experimental result show that the method of measurement on time-interval in pulsed laser ranging which uses low frequency triangle reference signal can achieve high precision. Besides, both improving the frequency of triangle reference signal and reducing the noise attached in triangle reference signal can effectively improve the precision of time-interval measurement.The numerical simulation and experimental results also confirm the feasibility of measurement on time-interval on pulsed laser ranging..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 212004 (2013)
Lasers and Laser Optics
Wavefront Propagation Modeling and Verification of the SG-II Updated Laser Facility
Guo Ailin, Zhu Haidong, Yang Zeping, Li Ende, Xie Xinglong, Zhu Jianqiang, Lin Zunqi, Ma Weixin, and Zhu Jian
Based on the diffraction theory, the specific beam structure and optics wavefront data of the SG-II updated laser facility, a calculation model of the wavefront propagation for the facility is established. Using the calculation model some important data for design and operation of the facility are gained, including theBased on the diffraction theory, the specific beam structure and optics wavefront data of the SG-II updated laser facility, a calculation model of the wavefront propagation for the facility is established. Using the calculation model some important data for design and operation of the facility are gained, including the corrected profile of deformed mirror, dynamic wavefront aberration of the amplifier, wavefront aberration and focus of the spatial filter, which are difficult to get by experiment. Analysis and comparison under three types of conventional operation, such as static propagation, static propagation and large energy shot with adaptive wavefront correction, indicates that the theoretical results are in good agreement with the experimental data. And the wavefront propagation of large energy shot in absence of the adaptive wavefront correction is calculated. The wavefront propagation model can be used to improve design of the related devices, optimize operation and control mode of the laser facility, and improve wavefront quality of the output laser beam..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 214001 (2013)
Experimental Study of HgCdTe Imaging Sensor Irradiated by TEA-CO2 Laser
Lei Peng, Li Hua, Bian Jintian, and Nie Jinsong
The disturbance and damages of TEA-CO2 laser to HgCdTe imaging sensor are researched experimentally and theoretically. The saturation of pixels of the HgCdTe detector just appears inside the facula when the energy density on it is less than 255 mJ/cm2. Pixels are damaged when the energy density is 425.8 mJ/cm2, and a dThe disturbance and damages of TEA-CO2 laser to HgCdTe imaging sensor are researched experimentally and theoretically. The saturation of pixels of the HgCdTe detector just appears inside the facula when the energy density on it is less than 255 mJ/cm2. Pixels are damaged when the energy density is 425.8 mJ/cm2, and a dispersed spot and a dark ring are observed. By the simulation of the HgCdTe detector under CO2 laser irradiation, the temperature distribution of the detector is calculated. The relationship among temperature-rise, carrier density and mobility of the detector is discussed. The dispersed spot occurs because of free carriers excited by heat diffuse under carrier density grades. The dark ring appears because of both of the mobility changing and carrier density diffusing. Hg atoms separate out from the detector due to their high temperatures, resulting in the pixels damage..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 214002 (2013)
Experimental Research on the Transmission Wave-Front Characteristic of High Power Slab Gain Module in Resonator
Li Mi, Hu Hao, Wu Yingchen, Zhao Na, Li Jianmin, Du Yinglei, Lei Jun, and Shi Yong
Experimental research about the transmission wave-front characteristic of high power slab gain module in resonator is carried out. The measurement of transmission wave-front of slab gain module under different power extraction status is finished through changing the parameters of the resonator. The experiments indicateExperimental research about the transmission wave-front characteristic of high power slab gain module in resonator is carried out. The measurement of transmission wave-front of slab gain module under different power extraction status is finished through changing the parameters of the resonator. The experiments indicate that the power extraction status influences the transmission wave-front of slab evidently. Compared with the plano-concave resonator and the asymmetric output plano-plano resonator, the transmission wave-front distortion of the slab gain module is the minimal with the symmetrical output plano-plano resonator, the peak-to-valley (PV) value of the wave-front distortion is less than 1.5 μm when the pumping power is 10.8 kW..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 214003 (2013)
Machine Vision
Fisheye Image Matching Based on Rotation Matrix under Spherical Perspective Projection
Zhu Haijiang, Xu Xiaobo, and Zhou Jinglin
A stereo matching algorithm based on spherical perspective projection model for fisheye images which have severe distortions and a large field of view with 180° is presented. Only estimating the focal length and the principal point of two fisheye images, all feature points on two fisheye images are first projectedA stereo matching algorithm based on spherical perspective projection model for fisheye images which have severe distortions and a large field of view with 180° is presented. Only estimating the focal length and the principal point of two fisheye images, all feature points on two fisheye images are first projected onto two spherical perspective images. Then rotation matrix and translation vector between two spherical perspective images are computed to find two corresponding spherical image patches, which are mapped into two fisheye images. And these estimated parameters are refined through minimizing the re-projected error of all feature points on the spherical perspective images. The corrected correspondence points between two fisheye images are determined through the refined rotation and translation. Experiments with real fisheye images show that this method has satisfactory matching results for the severely distorted fisheye images..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 215001 (2013)
Three-Dimensional Measurement Data Registration Based on Planar Circle Target
Wei Xinguo, Liu Tao, and Liu Zhen
A three-dimensional (3D) data registration method based on planar circular target is proposed to solve the problem of 3D data registration in the vision measurement of large-scale object surface profile. With the planar circular target placed in front of the measured object, 3D vision system takes photographs of planarA three-dimensional (3D) data registration method based on planar circular target is proposed to solve the problem of 3D data registration in the vision measurement of large-scale object surface profile. With the planar circular target placed in front of the measured object, 3D vision system takes photographs of planar circular target at adjacent measurement positions. Then the planar circular target is used as an intermediary, and registration of 3D measurement data from adjacent measurement positions is achieved by establishing correspondence between edge points in circle. As shown in experiments, the data registration root mean square (RMS) error of x, y and z, with considerable accuracy of the planar grid target method, is 0.06, 0.03 and 0.134 mm respectively. When the measured object is partly occluded, the data registration RMS error of x, y and z is 0.06, 0.03 and 0.168 mm respectively. While the method of planar grid target fails to registration because of mismatch of 3D grid data..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 215002 (2013)
Materials
Preparation and Optical Properties of Ce3+-Doped High Lutetium-Gadolinium Oxide Glasses
Yang Bin, Zhang Yuepin, Xu Bo, and Xia Haiping
A kind of high lutetium-gadolinium borosilicate glass is prepared by high temperature melting method at different temperatures. Formation range of this glass system is experimentally studied and their density and thermal stability is measured. It is found that the glass phase is wide, and the glass has well thermal staA kind of high lutetium-gadolinium borosilicate glass is prepared by high temperature melting method at different temperatures. Formation range of this glass system is experimentally studied and their density and thermal stability is measured. It is found that the glass phase is wide, and the glass has well thermal stability as well as high density that is up to 5 g/cm3. The transmission, emission, excitation spectra, emission spectra under X-ray excitation and decay curves of Gd3+ ions of Ce3+-doped glass are measured. The results show that the transmission performance of glass is appropriate for Ce3+ ion doping, and both Gd2O3 and Lu2O3 have a positive influence on scintillator emission, Gd3+ ion and Ce3+ ion energy transfer mechanism and the doping concentration for best energy transfer are studied. Considering the physical properties and optical properties of glass, the scintillation glass system has a certain potential applications in high-energy physics material..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 216001 (2013)
First-Principle of the Electronic Structure and Optical Property of LaBr3 Under High Pressure
Mao Xiaoli, Ge Yixian, Ma Tao, and Zhang Jiahong
Crystal structure and electronic and optical properties of LaBr3 under high pressure are systematically investigated by first-principles method within the local-density approximation (LDA). The calculated lattice parameters and bulk modulus are in good agreement with the experimental data reported. The results of the bCrystal structure and electronic and optical properties of LaBr3 under high pressure are systematically investigated by first-principles method within the local-density approximation (LDA). The calculated lattice parameters and bulk modulus are in good agreement with the experimental data reported. The results of the band structure calculation show that LaBr3 is a direct-band-gap insulator without pressure, and the top of the valence band is mainly composed of Br 4p states while the lower part of the conduction band is dominated by the La 5d states. Under high pressure, LaBr3 gradually transforms into an indirect-band-gap insulator while the band gap presents a basically linear reduction trend with the increase of pressure. Analysis of the optical properties shows that the transmittance of LaBr3 reaches 80% in the visible and infrared region, indicating that LaBr3 is an ideal transparent material. With the increase of pressure, two higher peaks of the imaginary part of the dielectric function, the optical absorption edge and the optical transmittance edge are red-shifted. Furthermore, the static dielectric constant, the refractive index and the reflectivity of LaBr3 increase gradually. In a word, the involved results show that the high pressure effectively modulates the electronic structure and optical properties of LaBr3, which can provide a theoretical basis for the design and application of LaBr3 optoelectronic materials..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 216002 (2013)
Medical Optics and Biotechnology
Method to Improve Axial Resolution of Spectral Domain Optical Coherence Tomography
Chong Bo, and hu Yongkai
In spectral domain optical coherence tomographic system, group velocity dispersion of broadband light source reduces axial resolution and leads to the decrease of image resolution and contrast. The decline of axial resolution of spectral domain optical coherence tomography (SD-OCT) caused by dispersion is analyzed and In spectral domain optical coherence tomographic system, group velocity dispersion of broadband light source reduces axial resolution and leads to the decrease of image resolution and contrast. The decline of axial resolution of spectral domain optical coherence tomography (SD-OCT) caused by dispersion is analyzed and a method based on spectrum correction to improve axial resolution of spectral domain optical coherence tomography is proposed. Spectrum coordinate is processed by second-order coefficients fitting. The coefficients are got by three-step threshold iteration. The axial depth is demodulated by the corrected spectrum. Spectral-domain optical coherence tomography experiments of single-layer thin glass and tomato epidermis tissue show that, compared with traditional method, the axial resolution is improved more than 10 μm and resolution of the two-dimensional tomogram is higher. It is generally applicative for different samples..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 217001 (2013)
Methodological Study on “Coarse-Grain” Diffuse Optical Tomography Based on Region-Labeling: Continuous-Wave Mode
Wu Linhui, Zhao Huijuan, Yi Xi, Zhang Wei, and Gao Feng
A region-labeling approach of image reconstruction under continuous-wave mode is developed for “coarse-grain” diffuse optical tomography (DOT). The method is based on the framework of the pixel-based DOT methodology and on an assumption that different anatomical regions have their respective sets of homogeneous opticalA region-labeling approach of image reconstruction under continuous-wave mode is developed for “coarse-grain” diffuse optical tomography (DOT). The method is based on the framework of the pixel-based DOT methodology and on an assumption that different anatomical regions have their respective sets of homogeneous optical parameter distributions. The proposed scheme is validated using a three-dimensional (3D) digital mouse atlas, the optical parameters of the organs could be simultaneously reconstructed at 60 dB, 40 dB and 20 dB noise levels. Physical experiments on a phantom are also conducted to evaluate the performance of the method. The reconstructed results show that the region-labeling DOT solution greatly improves the ill-posedness of the inverse problem as well as the imaging resolution and quantitative accuracy by reducing the number of unknowns to be reconstructed. The homogeneous optical parameters of each region can be reconstructed from noisy data..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 217002 (2013)
Optical Design and Fabrication
Design of Prism Spectrometer with Wide Spectral Coverage for Solar Spectrum Measurement
Zhang Hao, Fang Wei, Ye Xin, and Zhang Guangwei
A satellite-borne solar spectrometer with wide spectral coverage is designed to routinely monitor the long-term variability of solar spectral irradiance (SSI) outside the atmosphere. The instrument employs only one prism with curved surfaces for the dispersion of solar spectrum from 250 nm to 2500 nm, which are scannedA satellite-borne solar spectrometer with wide spectral coverage is designed to routinely monitor the long-term variability of solar spectral irradiance (SSI) outside the atmosphere. The instrument employs only one prism with curved surfaces for the dispersion of solar spectrum from 250 nm to 2500 nm, which are scanned simultaneously by several detectors on the focal plane as the prism rotates. The spectral response function (SRF) and spectral resolution of the instrument are also simulated based on Huygens wavelet point spread function (PSF). The tangential aberration of all the wavelengths is smaller than 8 μm at each prism rotation angle within ±2.5°. The wavelength resolution is 0.7～3.5 nm in ultraviolet region (250～400 nm), 3.5～35.0 nm in visual/near-infrared (400～1000 nm) and 28.5～41.2 nm in short-wave infrared (1000～2500 nm). The structure of the system is simple and compact, and the performance is stable and reliable. The spectral dispersion and aberration correction capacity satisfy demand of the long-term measurement of SSI at the top of atmosphere..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 222001 (2013)
Optical System Design and Simulation of LED Line Source for Ultraviolet Curing
Kong Xiaohui, Bai Tingzhu, and Yang Yali
An application research on 365 nm ultraviolet LED used in the field of ultraviolet curing is performed, and a technical method using Fresnel lens to replace traditional cylindrical lens is suggested to realize line focusing of the light source. The design process and simulation results are provided. Based on foregone fAn application research on 365 nm ultraviolet LED used in the field of ultraviolet curing is performed, and a technical method using Fresnel lens to replace traditional cylindrical lens is suggested to realize line focusing of the light source. The design process and simulation results are provided. Based on foregone flat Fresnel lens design formulae, determination basis of fundus thickness and focus with known clear aperture diameter and focus range is deduced. The optical system includes point-focusing Fresnel lens and line-focusing Fresnel lens. The models of Fresnel lens optical system and cylindrical lens optical system are established with a tracepro software. Important indexes including energy utilization efficiency and irradiance uniformity are analyzed with ray tracing. Simulation results show that the optical system using Fresnel lens can reach the optical technological indexes on the target plane and provide higher energy utilization efficiency and irradiance uniformity..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 222002 (2013)
Design and Distortion Characteristics Analysis of the Large-Image-Field Off-Axis Three-Mirror Telescope
Chen Yang, and Wang Yueming
The low-distortion, large-image-field telescope is the key to the precise image fusion and registration of wide-band hyperspectral imaging system. Based on the analytical methods and vector aberration theory, the distortion of the off-axis three-mirror optical system is analyzed. A new method to design the low-distortiThe low-distortion, large-image-field telescope is the key to the precise image fusion and registration of wide-band hyperspectral imaging system. Based on the analytical methods and vector aberration theory, the distortion of the off-axis three-mirror optical system is analyzed. A new method to design the low-distortion off-axis three-mirror optical system is proposed. A coaxial three-mirror optical system is designed by analytical methods and then the original system is made off-axis. Then the system is optimized according to analysis based on the vector aberration theory. An optical system is designed which is characterized by the system focal length of 1000 mm, cross track field of 5.6°, along track field of 1° and F number of 5. The maximum distortion measured by Zemax software is only 0.0628%. This method can be applied to design telescopes not only in the large-field and high-resolution imaging spectrometer system, but also in the occasions that demand low distortion..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 222003 (2013)
Laser Processing Lens of Long Focal Depth and High Resolution
Wang Zhongxun, Pan Yiming, Yin Shaoyun, Deng Qiling, Shi Lifang, Du Chunlei, and Wu Qinzhang
Limited by the contrary relationship of the focal depth and the focal size, it is hard to enlarge the fabrication depth while keeping high resolution for laser processing. To solve this problem, a design method for realizing Fresnel lens with long focal depth and small focal size by phase sampling and combination is prLimited by the contrary relationship of the focal depth and the focal size, it is hard to enlarge the fabrication depth while keeping high resolution for laser processing. To solve this problem, a design method for realizing Fresnel lens with long focal depth and small focal size by phase sampling and combination is proposed. A laser processing lens for drilling holes on paper with aperture of 11 mm and center focal length of 47 mm, working at the wavelength of 10.6 μm, is designed by using a homemade program. Then it is fabricated and tested. The experiment results show that, compared with traditional lens with the same aperture, this lens has a 2 times longer focal depth, and the focal size is similar to that of the traditional lens along the entire focal depth. This lens is simple to realize and it provides a feasible way to achieve long focal depth and high resolution synchronously. The advantages make it with great application potential in the field of laser processing..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 222004 (2013)
Optical Devices
Theoretical Analyesis and Preliminary Fabrication of Ti-Diffused LiNbO3 Ridge Waveguides
Li Jinyang, Yao Yanqing, Wu Jianjie, and Qi Zhimei
Lithium niobate (LN) ridge waveguides have recently attracted considerable attention, and they are usually fabricated by etching LN channel or slab waveguides prepared by Ti indiffusion or proton exchange. The field profile of the fundamental transverse electric (TE) mode guided in each of the two LN ridge waveguides cLithium niobate (LN) ridge waveguides have recently attracted considerable attention, and they are usually fabricated by etching LN channel or slab waveguides prepared by Ti indiffusion or proton exchange. The field profile of the fundamental transverse electric (TE) mode guided in each of the two LN ridge waveguides converted from the Ti-indiffused channel and slab waveguides is simulated at 1550 nm wavelength. The simulation results indicate that the LN slab waveguide can offer the resulting ridge structure a stronger confinement of the TE mode as compared with the channel waveguide made under the same Ti-indiffusing conditions. The strong confinement of the guided mode allows for miniaturizing the LN-based photonic devices and for enhancing the electro-optical overlapping factor. It is also simple to fabricate the ridge structure from LN slab waveguides. On the other hand, Ti-indiffused LN slab waveguides are prepared, on which a chromium layer with a pattern of Mach-Zehnder interferometer (MZI) array is fabricated by the micro electro mechanical systems (MEMS) process. The ridge waveguide MZI array is realized by reactive ion etching of the slab LN waveguide in the SF6 atmosphere. Investigations by scanning electron microscopy reveal that the prepared LN ridge waveguides have a ridge height of 670 nm and an isosceles trapezoid cross section and their sidefaces are rather coarse..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 223001 (2013)
Influence of Flexoelectric Effect on Guided Mode of Hybrid-Aligned Nematic Liquid Crystal
Xing Hongyu, Ye Wenjiang, Si Libin, Li Zhiguang, Zhang Zhidong, and Xuan Li
The flexoelectric effect has an influence on the distribution of liquid crystal in the strong anchoring hybrid-aligned nematic (HAN) liquid crystal cell, which can be measured by the improved full-leaky guided mode technique of liquid crystal. Based on the multi-layer optical theory and the elastic theory of liquid cryThe flexoelectric effect has an influence on the distribution of liquid crystal in the strong anchoring hybrid-aligned nematic (HAN) liquid crystal cell, which can be measured by the improved full-leaky guided mode technique of liquid crystal. Based on the multi-layer optical theory and the elastic theory of liquid crystal, the variation curves between the reflectivity and transmittance of the full-leaky liquid crystal waveguide due to the strong anchoring hybrid-aligned nematic liquid crystal and the internal angle (the angle of incidence for which light is incident on the liquid crystal layer) are calculated theoretically, by which the influence of flexoelectric effect is analyzed. For different sign of the flexoelectric coefficient such as negative or positive, the variation curves of reflectivity or transmittance of the full-leaky liquid crystal waveguide will move a distance to the left or the right relative to the case of ignoring the flexoelectric effect, and the moved distance will vary with the different flexoelectric coefficients. The flexoelectric coefficients can be known from the moved distance, which provides the theoretical basis for determining the flexoelectric coefficients..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 223002 (2013)
Optics in Computing
Separation Research of Measurement Matrices Based on 0-1 Sparse Circulant Matrix
Cheng Tao, Zhu Guobin, and Liu Yu′an
Current optimization of measurement matrix of compressive sensing is optimization beforehand by using the same matrix in measurement and reconstruction stages. Transition matrix and optimization algorithm mainly based on row transformation are proposed to separate the measurement matrix and reconstruction matrix of comCurrent optimization of measurement matrix of compressive sensing is optimization beforehand by using the same matrix in measurement and reconstruction stages. Transition matrix and optimization algorithm mainly based on row transformation are proposed to separate the measurement matrix and reconstruction matrix of compressive sensing. 0-1 sparse matrix of single-pixel camera is adopted during measurement, while approximate matrix is adopted during reconstruction. It is a kind of afterwards optimization method of measurement data and measurement matrix, different from traditional thinking. Theory analysis and experiment results demonstrate that the characteristics of optimal matrix are better than circulant sparse matrix, and approximate matrix and optimal matrix have similar characteristics. The research results reduce the difficulty of engineering design and implementation of measurement matrix..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 220001 (2013)
Physical Optics
Comparison on the Scalar Diffraction Integral Formulae
Guo Fuyuan, and Li Lianhuang
As the Fresnel-Kirchhoff diffraction formula and the first and second solution of Rayleigh-Sommerfeld diffraction formulae coexist in the scalar diffraction integral formulae system, it is difficult to judge which one is the best. For the sake of comparing three diffraction formulae, the specialties of small diffractedAs the Fresnel-Kirchhoff diffraction formula and the first and second solution of Rayleigh-Sommerfeld diffraction formulae coexist in the scalar diffraction integral formulae system, it is difficult to judge which one is the best. For the sake of comparing three diffraction formulae, the specialties of small diffracted source and far field diffraction are employed to simplify three diffraction formulae, the expressions of the scalar far field total powers in observation plane and vector far field total powers in observation hemisphere are presented. Based on the convergence of integrand, the applicable scopes of three diffraction formulae are introduced. And using the total power of diffracted source as standard, the computational precisions of the diffraction formulae are clarified. The analysis results indicate that, for the hypothesis of scalar diffraction field, three diffraction formulae are suitable for computing the paraxial scalar diffraction beam, but only the first solution of Rayleigh-Sommerfeld diffraction formula is appropriate for computing the non-paraxial diffraction beam. For the nature of vector diffraction field, three diffraction formulae are applicable for computing the paraxial and non-paraxial vector diffraction beam. Hereinto, for the normal incident plane wave diffracted by small circular aperture, the absolute value of relative calculated error of the far field total power which is computed by the second solution of Rayleigh-Sommerfeld diffraction formula is the least..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 226001 (2013)
Quantum Optics
Dependence of Continuous Variable Entanglement Enhancement on Experimental Parameters
Jia Xiaojun, Duan Zhiyuan, and Yan Zhihui
Continuous variable entangled state of light with quantum correlation in quadrature amplitude and quadrature phase is the key resource to realize quantum information and quantum computation processing. With the rapid development of quantum information and quantum computation, correlation degrees of entangled state of lContinuous variable entangled state of light with quantum correlation in quadrature amplitude and quadrature phase is the key resource to realize quantum information and quantum computation processing. With the rapid development of quantum information and quantum computation, correlation degrees of entangled state of lights have to be enhanced to match the requirement of high-quality information transfer and high-efficiency quantum computation. Continuous variable entanglement enhancement is an efficient method for the generation of entangled state of light with high entangled degree. The relation between the continuous variable entanglement enhancement and the experimental parameters of non-degenerate optical parametric amplifier is calculated. The influence of these experimental parameters on the entanglement enhancement is also discussed. This provides the direct references for optimizing the continuous variable entanglement enhancement system consisting of non-degenerate optical parametric amplifier..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 227001 (2013)
Remote Sensing and Sensors
Development of Three-Wavelength-Raman-Polarization Lidar System and Case Study
Liu Dong, Tao Zongming, Wu Decheng, Wang Zhenzhu, Wang Bangxin, Zhong Zhiqing, Bo Guangyu, Xie Chenbo, Zhou Jun, and Wang Yingjian
Atmospheric aerosol and cirrus clouds modulate the balance of the radiation budget between the earth and its atmosphere, through their direct, indirect effect and the reaction of each other. In order to study microphysical properties of atmospheric aerosol and physical properties of cirrus cloud, a three-wavelength-RamAtmospheric aerosol and cirrus clouds modulate the balance of the radiation budget between the earth and its atmosphere, through their direct, indirect effect and the reaction of each other. In order to study microphysical properties of atmospheric aerosol and physical properties of cirrus cloud, a three-wavelength-Raman-polarization lidar system is developed, which is composed of transmitter, receiver, control, and data acquisition subsystems. It has many advanced characteristics, such as multiply wavelengths, large detecting range, fine temporal and range resolution, good detection sensitivity and reliable data. The backscattering coefficients of 355, 532 and 1064 nm, extinction coefficients of 355 nm and 532 nm, and depolarization ratio of 532 nm can be retrieved from this lidar system. Case study indicates that the data acquired from this lidar are reliable and can be used for study of the microphysical properties of the aerosol and cirrus cloud..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 228001 (2013)
Research on High-Accuracy in-Flight Spectral Calibration of the Solar Backscattered Ultraviolet Spectroradiometer
Li Zhanfeng, Wang Shurong, Huang Yu, and Yu Xiangyang
A new high-accuracy spectral calibration is applied to monitor and correct spectral shift of solar backscattered ultraviolet spectroradiometer (SBUS) in launch and flight. A high-resolution reference spectrum is used to convolve with instrument′s slit function. The convolved results is matched with corrected spectrum mA new high-accuracy spectral calibration is applied to monitor and correct spectral shift of solar backscattered ultraviolet spectroradiometer (SBUS) in launch and flight. A high-resolution reference spectrum is used to convolve with instrument′s slit function. The convolved results is matched with corrected spectrum measured by SBUS, and evaluation function is founded to calculate the value of the spectral shift that minimizes the difference between reference and measured spectrum. For SBUS, the optimal spectral shift is 0.10 nm. Finally, the result is validated by standard spectrum of on-board mercury lamp and the maximal error is 0.01 nm, which meets instrument′s requirements. The experimental results verity feasibility and precision of the high-accuracy spectral calibration..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 228002 (2013)
Acceleration Sensor Based on Laser Self-Mixing Interference
Yang Ying, Li Xingfei, Li Hongyu, Wang Cuo, and Kou Ke
A novel acceleration sensor based on laser self-mixing interference is proposed. The structure and principle of the accelerometer are introduced. The influence of different factors on its resolution and their influencing mechanism are analyzed. The pendulous reed supported by dual flexible beam is used as the first steA novel acceleration sensor based on laser self-mixing interference is proposed. The structure and principle of the accelerometer are introduced. The influence of different factors on its resolution and their influencing mechanism are analyzed. The pendulous reed supported by dual flexible beam is used as the first step sensing unit. When an inertial force due to acceleration is applied in the pendulous reed, a displacement proportional to the acceleration occurrs to the pendulous reed, which changes the length of external cavity. The phase of self-mixing interference signals generated by laser which is modulated by sawtooth-wave current is a function of acceleration. All-phase spectrum analysis is applied to detect the phase of self-mixing interference signals to reconstruct the displacement of the pendulous reed and the acceleration. A simulation model of the acceleration sensor is established. The simulation results show that the scheme is feasible. Its performances are measured through experiments. Experimental results show that the resolution of the acceleration sensor is 0.19 μg, which consistant with the retical analysis. The acceleration sensor based on laser self-mixing interference can achieve a high resolution..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 228003 (2013)
Effect of Diectric-Layer Parameter Coated on Microtube Inner Wall Surface on Optofluidics Biosensor Sensitivity
Ji Qiang, Jiang Junfeng, Liu Tiegen, Liu Kun, Liu Wenhui, Zhang Jing, and Chen Wenjie
The sensitivity enhancement effect of microtube coated with a dielectric layer on the inner surface is presented. The simulations of mode-field distribution and senstivity are carried out for thin wall microtubes and thick wall microtubes with an established four-layer ring structure model. The results show that opticaThe sensitivity enhancement effect of microtube coated with a dielectric layer on the inner surface is presented. The simulations of mode-field distribution and senstivity are carried out for thin wall microtubes and thick wall microtubes with an established four-layer ring structure model. The results show that optical field energy in the core of the microtube can be increased when a dielectric layer with high refractive index is coated on the inner wall surface of the microtube, thus the sensitivity is enhanced. The sensitivity of the 1st-order radial mode of the thin wall microtube and the high-order radial mode of the thick wall microtube are enhanced by 65 and 302 times, respectively. The refractive-index sensing sensitivity of the high-order radial mode will experience multiple peaks accompanying with the thickness change of the dielectric layer, which is analyzed from the view of geometrical optics..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 228004 (2013)
Spectroscopy
Near-Field Mechanism Research on Hyperspectral Image Plane Interferometric Imaging
Meng Xin, Li Jianxin, Zhu Rihong, Zhou Wei, and Yao Liangtao
The technology of image plane interferometric imaging has the advantages of high luminous flux, high target resolution and high spectral resolution. It is mainly applied in remote sensing imaging field. In order to achieve the near-field target detection, the theory of near-field image plane interferometric imaging is The technology of image plane interferometric imaging has the advantages of high luminous flux, high target resolution and high spectral resolution. It is mainly applied in remote sensing imaging field. In order to achieve the near-field target detection, the theory of near-field image plane interferometric imaging is analyzed. The factors affecting image quality is studied and the physical expressions of optical path difference and the minimum detection are described. The modulation influencing factors of near-field image plane interferometric fringe are studied and the calculation method of modulation is deduced. The impact of the interferometric fringe modulation on the signal-to-noise ratio and the accuracy of the recovery spectrum is analyzed. For improving the modulation of near-field interferometric imaging and the image quality, a re-imaging interferometric system is set up. Experimental device of imaging plane interferometric spectrometer is set up to detect the near-field targets and the experimental interferometric images are analyzed. A re-imaging experimental device is set up and we get a series of near-field target interferometric images with high modulation..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 230001 (2013)
New Method for Eliminating Background Fluorescence of Raman Spectrum and Its Application
Gao Guoming, Li Xue, Qin Zongding, Wei Kunlian, Huang Hanming, Liu Junxian, and Yao Huilu
Raman signal, especially signal from living organisms, sometimes is interfered so seriously by the background fluorescence that it is too complex to get good result. According to the characteristics of fluorescence background, a new fluorescent background method based on min-max signal adaptive zooming is developed. ToRaman signal, especially signal from living organisms, sometimes is interfered so seriously by the background fluorescence that it is too complex to get good result. According to the characteristics of fluorescence background, a new fluorescent background method based on min-max signal adaptive zooming is developed. To verify the feasibility of this method, two ways are used: one is the relation between peak intensity and concentration, the other is the relation between single spectrum and mixed spectra. Compared to the traditional fluorescent background elimination (polynomial fitting baseline correction), the results show that this method is highly feasible and superior to the traditional method. To image the 2D, 3D blood distribution in mice ear tissue in vivo, the peak at 1549 cm-1 which is one of characteristic peaks of hemoglobin is selected. By comparing the image results generated by this new method with the former process way, the results show this method can optimize the Raman spectral data, especially for low-density Raman characteristic peaks, so the imaging results are better..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 230002 (2013)
Scanning Frequency Optimization of Laser Absorption Spectroscopy
Chen Jiuying, Liu Jianguo, He Yabai, Xu Zhenyu, Li Han, Yao Lu, Yuan Song, Ruan Jun, He Junfeng, and Kan Ruifeng
The system performance of tunable diode laser absorption spectroscopy (TDLAS) is affected by the characteristics of laser, the characteristics of detector, the modulation parameters, control circuit of laser and acquisition circuit of signal, etc. The characteristics of laser and detector are determined by the level ofThe system performance of tunable diode laser absorption spectroscopy (TDLAS) is affected by the characteristics of laser, the characteristics of detector, the modulation parameters, control circuit of laser and acquisition circuit of signal, etc. The characteristics of laser and detector are determined by the level of present production-manufacturing. For direct absorptive method, the modulation parameters contain scanning amplitude and scanning frequency. Scanning amplitude is adjusted to obtain complete absorption signal. The optimization and selection of scanning frequency are discussed in detail. Aiming at this problem, the influence of scanning frequency on direct absorption signals is observed by experiment based on a certain theory in the present paper, and the basis and method of scanning frequency optimization are summarized by analyzing the signal characteristics including amplitude, peak width, adjusted coefficient determination, signal-to-noise ratio and integrated absorbance, etc. The result of the experiment provides a definite basis for the selection of scanning frequency in TDLAS direct absorptive method..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 230003 (2013)
Study of Concentration Retrieving Algorithm for Ammonia Based on Differential Optical Absorption Spectroscopy
Zhu Jin, Sun Dongmei, and Chen Ling
The method of differential optical absorption spectroscopy (DOAS) is applied to the retrieval of ammonia concentration. Genetic algorithm, wavelet transform and Kalman filtering are all studied to show the inversion accuracy of low-concentration ammonia based on the traditional DOAS algorithm. The results show that allThe method of differential optical absorption spectroscopy (DOAS) is applied to the retrieval of ammonia concentration. Genetic algorithm, wavelet transform and Kalman filtering are all studied to show the inversion accuracy of low-concentration ammonia based on the traditional DOAS algorithm. The results show that all the three algorithms have good denoise performance for ammonia absorption spectrum with low SNR. In the case of ammonia concentration lower than 7.6 mg/m3, the inversion accuracy for three improved algorithms is obviously improved compared with the traditional algorithm. Standard deviation and peak to peak value of the differential absorbance residuals based on Kalman filtering combining traditional polynomial fitting are 0.1349% and 0.6132%, respectively, which shows the best performace. The measurement error is within ±0.3%..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 230004 (2013)
Thin Films
Glass Substrate with Hemisphere Pits Surface for Light Trapping in Thin Film Solar Cells
Zhong Jianping, and Wang Qingkang
Glass substrate with novel compact hemisphere pits surface structure is studied. Based on rigorous coupled wave analysis (RCWA), the diffraction of the structured glass substrate is thematically calculated. It is found that this kind of glass substrate can effectively diffract the normal incident light. It has high hazGlass substrate with novel compact hemisphere pits surface structure is studied. Based on rigorous coupled wave analysis (RCWA), the diffraction of the structured glass substrate is thematically calculated. It is found that this kind of glass substrate can effectively diffract the normal incident light. It has high haze when the period is around 2.6 μm with long wavelengths of 0.6~0.8 μm. This glass substrate is utilized in thin film solar cells for light trapping in our simulation. Compared with flat thin film structure, the average absorption is enhanced by 18.7% within 0.3~0.8 μm and the absorption is enhanced by 17.9%~77.7% within 0.6~0.8 μm bandwidth for the structure with a period of 2.6 μm under normal illumination..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 231001 (2013)
Shadowing Masks for Thickness Uniformity in a Plane Planetary System
Guo Chun, Kong Mingdong, Liu Cunding, and Li Bincheng
In a deposition system containing a planar planetary substrate holder, models for film thickness distribution without and with shadowing mask are developed. The shadowing mask optimized by numerical computation method is applied to achieve good thickness uniformity, while the deposition efficiency of the evaporated matIn a deposition system containing a planar planetary substrate holder, models for film thickness distribution without and with shadowing mask are developed. The shadowing mask optimized by numerical computation method is applied to achieve good thickness uniformity, while the deposition efficiency of the evaporated material is taken into consideration in the optimization. Experimentally, the theoretically designed shadowing mask is used to control the thickness distribution of the MgF2 coatings deposited by electron beam evaporation on a flat substrate with a planar planetary system. Uniformity measurements based on the reflection spectra of single layer MgF2 films demonstrate that uniformities is better than 99.6%, while the deposition efficiency of the evaporated material is higher than 87.4%..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 231002 (2013)
Microstructure and Luminous Property of Multilayer SiNx/Si/SiNx Thin Films
Lin Juan, Yang Peizhi, and Hua Qilin
Multilayer SiNx/Si/SiNx thin films are deposited on silicon substrate by bipolar pulse reactive magnetron sputtering technology combined with rapid thermal process technology. Raman spectra and photoluminescence (PL) spectra are used to investigate the microstructure and luminous property of the films influenced by difMultilayer SiNx/Si/SiNx thin films are deposited on silicon substrate by bipolar pulse reactive magnetron sputtering technology combined with rapid thermal process technology. Raman spectra and photoluminescence (PL) spectra are used to investigate the microstructure and luminous property of the films influenced by different annealing temperatures. The results of Raman spectra show that crystal and amorphous silicon quantum dots have formed in multilayer SiNx/Si/SiNx films by the high temperature annealing, with the Xc of 30% and the average size of about 6.6 nm. But the results of PL indicate that the average size of the crystal and amorphous silicon quantum dots are about 3.79 and 3.03 nm, respectively. In addition, luminous mechanism of PL consists of the defect states of SiNx and the quantum effects of quantum dots and the defect states of SiNx is the main luminous mechanism..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 231003 (2013)
Robust Design of a High-Performance Laser Thin-Film Polarizing Beam Splitter with Low Layer Errors Sensitivity
Wu Suyong, Yang Kaiyong, and Tan Zhongqi
According to the robust design method of multilayer optical coatings based on layer errors sensitivity control concept, the spectral characteristics responding to layer parameters errors are researched comparatively within three different application solutions of a high-performance thin-film polarizing beam splitter (PAccording to the robust design method of multilayer optical coatings based on layer errors sensitivity control concept, the spectral characteristics responding to layer parameters errors are researched comparatively within three different application solutions of a high-performance thin-film polarizing beam splitter (PBS) in a novel orthogonal polarized dual-frequency laser. The inherent factor of film errors sensitivity of laser PBS is found by elaborately arranged numerical robust design experiments. A low layer errors sensitivity thin-film structure is robust designed for the high-performance laser PBS with moderate layer number and easy-manufacturable layer thicknesses. This PBS design solution is very suitable for mass production at low cost and high yield, which will play a positive role in the development, engineering and application of the orthogonal polarized dual-frequency laser..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 231004 (2013)
X-Ray Optics
Structure Design and Accuracy Testing of Monochromator in a Soft X-Ray Spectromicroscopic Beamline
Gong Xuepeng, Lu Qipeng, and Peng Zhongqi
In order to satisfy the technical requirement of soft X-ray microscopy beamline in Shanghai Synchrotron Radiation Facility (SSRF), whose key assembly monochromator is designed. Wavelength scanning movement principle of monochromator is described. Design scheme of wavelength scanning mechanism is discussed, and factors In order to satisfy the technical requirement of soft X-ray microscopy beamline in Shanghai Synchrotron Radiation Facility (SSRF), whose key assembly monochromator is designed. Wavelength scanning movement principle of monochromator is described. Design scheme of wavelength scanning mechanism is discussed, and factors affecting the angular repeatability of plane mirror and plane grating are analyzed in detail; switching mechanism of plane grating is described, and horizontal deviation, vertical deviation, roll angle precision, yaw angle precision and pitch angle precision are analyzed in detail; six-bar parallel mechanism is used for adjusting the UHV-chamber, and adjusting range and resolution of the bar are analyzed. The entire structure of monochromator is presented, and its precision testing is performed. Results show that the angular repeatability of plane mirror and plane grating are 0.166″ and 0.149″, and roll, yaw and pitch angular repeatability of plane grating switching mechanism are 0.08″, 0.12″ and 0.05″, indicating that structure design and precision of monochromator satisfy the technical demand..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 2, 234001 (2013)
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