Journals >Acta Photonica Sinica
Contents
2015
Volume: 44 Issue 9
30 Article(s)
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Research Article
A Modulation Sheme to Generate 24-GHz-Band Millimeter-wave-band Ultra-wideband Signal by Using Mach Zehnder Modulator
WANG Dong, DAI Bo, REN Li-qing, SHENG Bing, WANG Qi, and ZHANG Da-wei
A single-stage dual-drive Mach Zehnder modulator was employed for the generation of a 24-GHz-band ultra-wide-band signal. A theoretical model for signal generation was derived based on the modulation technique of a dual-drive Mach Zehnder modulator. By the numerical demonstration, an ultra-wideband signal of 5.8 GHz baA single-stage dual-drive Mach Zehnder modulator was employed for the generation of a 24-GHz-band ultra-wide-band signal. A theoretical model for signal generation was derived based on the modulation technique of a dual-drive Mach Zehnder modulator. By the numerical demonstration, an ultra-wideband signal of 5.8 GHz bandwidth was generated. The signal quality and the bandwidth were thoroughly investigated. The results show that residual local oscillation and low-frequency components can be efficiently suppressed if two modulating electrical signals with proper amplitudes are used. The bandwidth of the signal can be flexibly adjusted by simply controlling the pulse width of the input data signal. The millimeter ultra-wideband signal generator is a good candidate for the applications of automotive short-range radar, intrusion detection sensor and mobile radio services..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 9, 906001 (2015)
Combined Algorithm of Fibonacci-MMSE for Optical Fiber Fabry-Perot Sensor
YIN Jia-di, ZHOU Ci-ming, OU Yi-wen, and LI Meng-meng
A combined algorithm of minimum mean square error estimation and Fibonacci method for fiber Fabry-Perot interferometer was proposed. This united algorithm uses the Fibonacci method to quickly search a series of cavity length estimators and finds the one as demodulation gap which corresponds to the minimum mean square eA combined algorithm of minimum mean square error estimation and Fibonacci method for fiber Fabry-Perot interferometer was proposed. This united algorithm uses the Fibonacci method to quickly search a series of cavity length estimators and finds the one as demodulation gap which corresponds to the minimum mean square error value. The relationship between iteration number and demodulation accuracy was analyzed by simulation, and a temperature measurement experiment was carried out. The results show that, the average error of this algorithm is less than 2×10－5 pm theoretically, linear fit of actual cavity length is above 0.999 9, and dynamic range is up to 2.5 mm. In the experiment, the resolution of algorithm is 0.15 nm, corresponding to a temperature resolution of 0.03℃ with quick demodulation time 0.03 s, both high resolution and fast demodulation speed can be achieved..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 9, 906002 (2015)
All-opened Double-spacing Brillouin-Raman Multi-wavelength Fiber Laser
XU Lei, MA Wan-zhuo, WANG Tian-shu, ZHANG Peng, KONG Mei, and ZHANG Jing
An all-opened double-spacing Brillouin-Raman fiber laser was investigated. A C+L band tunable laser was used as Brillouin pump, a laser diode with 1 455 nm center wavelength was used as Raman pump and 7 km dispersion compensation fiber was used as gain medium. Stimulated Brillouin scattering and Raman amplification werAn all-opened double-spacing Brillouin-Raman fiber laser was investigated. A C+L band tunable laser was used as Brillouin pump, a laser diode with 1 455 nm center wavelength was used as Raman pump and 7 km dispersion compensation fiber was used as gain medium. Stimulated Brillouin scattering and Raman amplification were generated in the dispersion compensation fiber simultaneously and the odd-order and even-order Stokes light were obtained at the two ends of the dispersion compensation fiber respectively. The proposed configuration can reduce the insertion loss caused by multiple devices. The largest number of output channels is 186, the tuning range is 28.6 nm and the channel spacing is 0.154 nm. The side mode suppression ratio is enhanced from 14 dB to 20 dB by joining a segment of 4 m Erbium-doped fiber..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 9, 906003 (2015)
Mixed Noise Removal Based on Non-local Means Filter and SUSAN Operator
WU Yi-quan, WANG Kai, and DAI Yi-mian
To remove mixed noise better, which is composed of impulse noise and Gaussian noise, a mixed noise removal method based on non-local means filter and Small Univalue Segment Assimilating Nucleus(SUSAN) operator was proposed. Firstly, according to the difference of shape features of univalue segment assimilating nucleus To remove mixed noise better, which is composed of impulse noise and Gaussian noise, a mixed noise removal method based on non-local means filter and Small Univalue Segment Assimilating Nucleus(SUSAN) operator was proposed. Firstly, according to the difference of shape features of univalue segment assimilating nucleus between the impulse noise points and conner points, the method extracts many characteristic points by SUSAN operator, which contains mainly impulse noise points and may also contain a small part of corner points. The characteristic points are sorted. The points whose frequency of occurrence ranks top two are impulse noise points. Then, the mean of non-impulse noise points in the pulse noise point′s neighborhood is calculated by the improved mean filter method to replace the impulse noise points′s gray value. Finally, for the image whose impulse noise has been filtered, the remaining Gaussian noise is denoised by non-local means filter method. A large number of denoising experimental results show that, compared with the method combining adaptive median with weighted mean, the method combining median filter with wavelet transform, and the method combining pulse coupled neural network with median filter, the proposed method has better subjective visual effect, and preserves the edges and details of image better, and it has great improvement in objective quantitative evaluation indicators such as peak signal to noise ratio. The proposed method shows obvious advantages in removing mixed noise..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 9, 910001 (2015)
Infrared Dim and Small Target Detection Algorithm Based on Multi-scale Anisotropic Diffusion Equation
ZHOU Hui-xin, ZHAO Ying, QIN Han-lin, YIN Shi-min, LIU Gang, ZHAO Dong, YAN Xiang, and RONG Sheng-hui
For the poor performance of dim and small infrared target detection under complex background, a novel target detection algorithm inspired by the anisotropic diffusion equation and the multi-scale analysis was presented. Firstly, the raw target image is decomposed by the surfacelet transform into multi-scale and mutli-dFor the poor performance of dim and small infrared target detection under complex background, a novel target detection algorithm inspired by the anisotropic diffusion equation and the multi-scale analysis was presented. Firstly, the raw target image is decomposed by the surfacelet transform into multi-scale and mutli-direction details characteristics. Then, the improved anisotropic diffusion equation difference filter and the local mean removal filter are adopted to refine the high-frequency and the low-frequency subbands respectively. Reconstruct the refined subbands by the inverse surfacelet transform to obtain the result image with target enhancement and background suppression. Finally, the classical adaptive threshold segmentation method is used to implement target detection. Various infrared images with dim and small targets are used to verify the efficiency of the algorithm. Compared with wavelet filter and anisotropic diffusion equation filter, the experimental results show that the proposed algorithm can effectively suppress the background and its edge, and acquires a better performance of the target detection..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 9, 910002 (2015)
Infrared Dim-Small Target Tracking Based on Guide Filter and Spatio-Temporal Context Learning
QIAN Kun, ZHOU Hui-xin, QIN Han-lin, YIN Shi-min, RONG Sheng-hui, and ZHAO Dong
Because traditional target tracking algorithm don′t take full advantages of spatio-temporal relationships between the target and its local background, small target and edges can not be distinguished effectively, thereby the excursion problem occurs. Based on the Spatio-Temporal Context (STC) learning tracking algorithmBecause traditional target tracking algorithm don′t take full advantages of spatio-temporal relationships between the target and its local background, small target and edges can not be distinguished effectively, thereby the excursion problem occurs. Based on the Spatio-Temporal Context (STC) learning tracking algorithm, excursion problem was analyzed, and a new IR dim target tracking based on Guided Image Filter and STC is proposed. Guided Filter is adopted to preserve edges and eliminate the noise of context areas, and ideal context prior can be calculated after subtracting the filtering result from original image. Then, an ideal confidence map makes an accurate estimation of target. Several group of experimental results demonstrate that the presented method can track the target effectively, compared with several classical methods, such as improved template matching tracking, temporal-spatial fusion filtering algorithm and moving pipeline filtering algorithm. The experimental results show that the proposed algorithm performs well in terms of efficiency and accuracy..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 9, 910003 (2015)
Array Passive Ranging System Based on Orthogonal Wave-front Coding
CHEN Jia-feng, and LI Chun-fang
Aiming at the contradiction between maximum working distance and detecting accuracy for single-aperture orthogonal coding passive ranging system, a linear array orthogonal wavefront-coding ranging system consisting of multiple ranging sensors was established. The linear array geometry was given. The relation of OTF forAiming at the contradiction between maximum working distance and detecting accuracy for single-aperture orthogonal coding passive ranging system, a linear array orthogonal wavefront-coding ranging system consisting of multiple ranging sensors was established. The linear array geometry was given. The relation of OTF for array system and single-aperture system was obtained by summing multiple coding images from each sensor. The mathematic expression of optimal array separation for two-sensor array geometry was deduced. The minimum-redundancy linear array geometry can generate the more unique spacing responses and modulation cosine terms. The array response for multiple pair of sensors was obtained. The Cramer-Rao bound of range estimation was analyzed using Fisher information matrix. Theoretical and simulated results show that array ranging system can narrow bandpass region of range-dependent peak in the MTF, and lower minimum variance bound of range estimation, and improve detecting accuracy by double at least, as compared to the single aperture system for a given range..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 9, 911001 (2015)
Modified Multispectral Camera out-band Response Base on Correlation Spectrum
LI Xu-yang, YI Hong-wei, and HE Tian-bin
Multispectral remote sense camera can obtain geometic and spectral properties of the surface scenery, and will be wildly used in optical remote sense fields, but the blue spectrum of multispectral camera is more prone to out-band response. The paper established a mathematical model of multispectral remote sense camera′Multispectral remote sense camera can obtain geometic and spectral properties of the surface scenery, and will be wildly used in optical remote sense fields, but the blue spectrum of multispectral camera is more prone to out-band response. The paper established a mathematical model of multispectral remote sense camera′s spectral response, analyzed the reason of the blue band out-band response, and proposed blue spectrum out-band response correction method according to each spectral response relationship of multispectral remote sense camera used Time-Dealy-Integration Charge-Coupled-Device. Through statistics of typical objects obtain the correction formula of correction blue spectrum out-band response, the corrected residuals can be smaller than 4%, can meet the application requirement of multispectral remote sense camera. The correction results show that the correction method based on each spectral response has better applicability in correcting the blue spectrum out-band response..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 9, 911002 (2015)
Image Quality Evaluation on Extended Imaging of Telescopes
TAN Bi-tao, CHEN Hong-bin, and WANG Ji-hong
Based on the defects of single noises analysis or blur analysis in image quality evaluation, combined with telescope extended imaging characteristics, an image quality evaluation method under contrast and Structural similarity was designed and proposed, the basic principle, the specific implementation process as well aBased on the defects of single noises analysis or blur analysis in image quality evaluation, combined with telescope extended imaging characteristics, an image quality evaluation method under contrast and Structural similarity was designed and proposed, the basic principle, the specific implementation process as well as mathematical models of this method was given. The simulation image and measured image were used to validate the proposed method, validation results show that: the proposed evaluation method can give an effective evaluation value on sequence defocused image, noise image, defocused and noising image, the evaluation results close to human visual characteristics. The method can evaluate the image affected by noise and blur simultaneously effectively, and can give effective quantitative evaluation value. The evaluation results have high accuracy, monotony and consistency..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 9, 911003 (2015)
Studying the Combined Effects of Primary Aberrations on Gaussian Beam in High NA Focusing System
LI Hong-fu, XIE Hui-ming, ZHANG Chen, WANG Kai-ge, WANG Shuang, HE Qing-li, and BAI Jin-tao
For purpose of revealing the negative impacts of multiple primary aberrations in high numerical aperture optical system, the combined influence of the primary aberrations, especially coma, astigmatism and spherical aberration, on focusing Gaussian beam in high numerical aperture system was carried out based on diffractFor purpose of revealing the negative impacts of multiple primary aberrations in high numerical aperture optical system, the combined influence of the primary aberrations, especially coma, astigmatism and spherical aberration, on focusing Gaussian beam in high numerical aperture system was carried out based on diffraction theory. The intensity distribution of the Gaussian beam focal spot suffering multiple influence of coma, astigmatism and spherical aberration were acquired by numerical simulation. The results show that the impact of multiple abrration was not only superimposed of single aberration. In addition, a high consistency was found between the simulation results and the laser spots captured on the focal plane of a self-made high numerical aperture system, which indicated the reliability and reasonableness of the numerical simulation. The results present the optical distribution properties of Gaussian beam receiving multiple primary aberration effects, which will be helpful for evaluating and analyzing the practical optical focusing system..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 9, 912001 (2015)
Far-field Interference and Diameter Measurement on Two Coherent Plane Waves Irradiating Sphere
LI Jian-min, NIU Zhen-feng, WANG Yan-feng, SHAO Xue-hui, CHEN Fang, ZHANG Xiao-pan, LUO Jing, and YANG Fu
A theoretical model of the sphere far-field interference was given. When two coherent plane waves are irradiating the smooth sphere at any included angle, the reflected waves interfere in the far-field. A formula on optical path difference of reflected waves is derived in the far field. The sphere diameter can be accurA theoretical model of the sphere far-field interference was given. When two coherent plane waves are irradiating the smooth sphere at any included angle, the reflected waves interfere in the far-field. A formula on optical path difference of reflected waves is derived in the far field. The sphere diameter can be accurately measured with far field interference and a formula on measuring the diameter is given. The measurement system contains spectrometer, CCD camera, helium-neon laser, optical platform and computer. The method is given to measure the diameter of the sphere with original laser beam. The measured results of diameter by far-field interference are compared with that by the Abbe comparator, the relative difference of which is 0.2%. The measurement error generated by Gaussian beam is 5×10－5mm and can be negligible. This measurement method can achieve self-camera lens distortion correction. It shows that the theory and method of measurement is accurate. Gaussian laser beams is possible to measure the diameter of the sphere..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 9, 912002 (2015)
Attitude Parameters Determination by the Skylight Polarization Pattern
REN Jian-bin, LIU Jun, TANG Jun, WANG Chen-guang, ZHANG Nan, LI Da-lin, and YANG Jiang-tao
To address the issue of attitude determination for the autonomous navigation of the unmanned vehicles, an approach to define the pitch and roll angle of the vehicle by means of the stable distribution of skylight polarization pattern was proposed. Firstly, based on the Rayleigh scattering theory, we establish the theorTo address the issue of attitude determination for the autonomous navigation of the unmanned vehicles, an approach to define the pitch and roll angle of the vehicle by means of the stable distribution of skylight polarization pattern was proposed. Firstly, based on the Rayleigh scattering theory, we establish the theoretical and practical detected patterns of the polarized skylight. Secondly, through optimization, we obtain the data of the astronomical marker—the location of the sun based on the polarization data detected. Then, with respect to the relatively consistent space-time relation between the sun and the zenith, the location of the zenith is thus figured out. Finally, the coordinate of the zenith is adopted to establish the attitude rotation matrix and by which to work out the pitch and roll angles. In addition, by setting up a simulation vehicle platform to acquire the theoretical and practical polarization data, the effectiveness of the approach is tested. The calculated root-mean-square errors of the pitch angle are 0.002° and 0.0031° respectively for the theoretical and practical simulation test, and errors of the roll angle are 0.0236° and 0.0227° respectively. The results show that the approach to attitude determination through polarization detecting has advantages in easy handling and high accuracy..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 9, 912003 (2015)
Test of Optical Mirror Surface Using Fringe Reflection System
YUAN Ting, ZHANG Feng, TAO Xiao-ping, ZHOU Run, and FU Jin-jiang
Large shape errors can be found from the stage of fine grinding to the beginning of polish, it is proved that it can′t satisfy the measuring requirements to test the mirrors with profilers or ordinary interferometer in that stage. To obtain the optical mirrors′ shape error based on fringe reflection, the method of highLarge shape errors can be found from the stage of fine grinding to the beginning of polish, it is proved that it can′t satisfy the measuring requirements to test the mirrors with profilers or ordinary interferometer in that stage. To obtain the optical mirrors′ shape error based on fringe reflection, the method of high precision and large dynamic is proposed. The principle and system errors of the testing system were analyzed. To verify the feasible of the testing system, the model of testing on a reflecting mirror (the aperture is 100 mm) was built and simulated by ray tracing. The preliminary testing data on rotational symmetry spherical mirror is: PV is 0.523 μm, RMS is 0.086 μm, The feasibility of the testing system based on fringe reflection used in this period is verified..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 9, 912004 (2015)
Measurement of Half-wave Voltage of Electro-optic Crystal Based on Crystal Wedge
PEI Li-yan, MA Jing, XU Can-hua, QIU Xin-mao, and XU Qi-feng
The half-wave voltage was obtained by measuring the phase retardation of the electro-optic crystal under the applied external voltage. Based on polarization interference of birefringent crystal, phase shift of polarized light is transferred to the movement of interference fringes, and the linear accurate measurement isThe half-wave voltage was obtained by measuring the phase retardation of the electro-optic crystal under the applied external voltage. Based on polarization interference of birefringent crystal, phase shift of polarized light is transferred to the movement of interference fringes, and the linear accurate measurement is complemented by locating dark fringes position.The experimental results indicate that the accuracy of phase retardation of lithium noibate crystal is 4.4×10－3 rad, the half-wave voltage that LN crystal is measured as 480.0 V with experimental error of 0.10%. Compared with the experimental error of 0.96% that half-wave voltage is measured by extremum method, the measuring error of polarization interferometry method is reduced obviously. The optical structure of polarization interferometry method is simple with high measuring accuracy, the measurement result is insensitive to the power fluctuation of the light source and the measurement range of phase retardation of electro-optic crystal can be largely expanded..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 9, 912005 (2015)
New Type Spatial Soliton Pairs Based on Two-photon Photorefractive Effect
JIANG Qi-chang, and SU Yan-li
The solutions of new type spatial soliton pairs supported by both linear and quadratic electro-optical effects were deduced theoretically. The influences of external electric field on the intensity envelopes of bright-bright, dark-dark and bright-dark spatial soliton pairs were analyzed by numerical simulation method. The solutions of new type spatial soliton pairs supported by both linear and quadratic electro-optical effects were deduced theoretically. The influences of external electric field on the intensity envelopes of bright-bright, dark-dark and bright-dark spatial soliton pairs were analyzed by numerical simulation method. The results show that the new type bright-bright soliton pair can exist whether the external electric field is positive or negative, which is different from the soliton pair supported by the sole nonlinear effect. The soliton pair width supported by positive electric field is smaller than that of negative electric field. Because the different mechanism between the quadratic and linear electro-optical effects, the intensity of external electric field is restricted to a low certain range for dark-dark soliton pairs, and its width decrease gradually with the increasing of electric field intensity. For the new type bright-dark soliton pair, the peak of bright component is usually larger than that of dark component and the propagation instability will emerge when the propagation distance exceed a certain value under a certain amplitude perturbation..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 9, 919001 (2015)
Generation of Hollow Beams by a Plasma Channel Induced by Pump Pulses
TAN Chao, SHI Xiao-hui, TANG Yang-lin, DENG Yang-bao, and FU Xi-quan
The generation of hollow beams were demonstrated by using a plasma channel induced by pump pulses. A plasma channel will be generated as femtosecond pulses propagating in the nonlinear media, the distribution of refractive index in the plasma channel induced by pump beams is similar to a graded-index lens, besides, lasThe generation of hollow beams were demonstrated by using a plasma channel induced by pump pulses. A plasma channel will be generated as femtosecond pulses propagating in the nonlinear media, the distribution of refractive index in the plasma channel induced by pump beams is similar to a graded-index lens, besides, laser beams can only propagate in the plasma if the electron density of the plasma is less than the critical value, the probe beam is refracted and transformed into a hollow beam when it passes through in the periphery of the plasma channel. It finds that the probe beam begins to transform into a characteristic hollow beam structure when the power is 8 mW. When the power or repetition rate of the pump beam and the electron density in the plasma channel are changed, the region of the plasma where the probe beam can pass through is also changed, resulting in a controllable dark spot of the hollow beam..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 9, 919002 (2015)
Coupling Error Inhibition of Eccentric Adjustment Mechanism Design in Lithographic Objective Lens
ZHANG De-fu, LI Xian-ling, DONG Li-jian, and SUN Zhen
To identify the generated source of coupling errors, design method of the flexible eccentric mechanism is discussed in the paper. Firstly, the composition and working principle of the mechanism is given. Then, the mechanism model is established based on the compliance matrix method(CMM). Compliance of the bridge-type dTo identify the generated source of coupling errors, design method of the flexible eccentric mechanism is discussed in the paper. Firstly, the composition and working principle of the mechanism is given. Then, the mechanism model is established based on the compliance matrix method(CMM). Compliance of the bridge-type displacement amplification mechanism, the guiding mechanism and the connecting mechanism is derived. Finally, compliance of the whole body is got. The results show that the output compliance error is 8.126% obtained by the CMM and FEA method. The first natural frequency of the mechanism is 73.78 Hz. The stroke of the mechanism is 66.466μm when the driving force is no more than 40N. The maximum stress on lens and mechanism is 0.0711MPa and 235.22 MPa, respectively. The coupling error ratios between Y/Z/RX/RY/RZ and X stroke are 0.0543%, 0.0082%, 1.218×10－8rad/μm, 1.870×10－7rad/μm and 6.073×10－7rad/μm. PV and RMS of the lens surface figure after adjusting are better than 24nm and 5nm, respectively. It is mainly astigmatism. The mechanism is almost completely decoupled by reasonable flexibility design, which reveals that unreasonable compliance is the root of the generated coupling errors in adjusting..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 9, 922001 (2015)
Design of the Moon Simulator with Large Diameter Based on LightTools and Precision Analysis
LIU Shi, ZHANG Guo-yu, SUN Gao-fei, WANG Ling-yun, and GAO Yu-jun
In order to meet the requirements of observations of the moon as its target by navigation sensors and rendezvous and docking sensor, the moon simulator with large diameter and high irradiation uniformity was designed,the effective irradiation area is Φ2 000 mm. Using LightTools software, the phases, radiance and uniforIn order to meet the requirements of observations of the moon as its target by navigation sensors and rendezvous and docking sensor, the moon simulator with large diameter and high irradiation uniformity was designed,the effective irradiation area is Φ2 000 mm. Using LightTools software, the phases, radiance and uniformity of the moon simulator were designed, simulated and analyzed by modeling and tracing method. The phases of the moon and radiance control system was designed to control the 14 typical phases and radiance of the moon in real time. The radiance correction method of the LED array was put forward to improve the uniformity of the simulator. The test results show that the irradiation uniformity of the simulator is better than 15.7% after correction. It indicated that the simulator can be used as the target for sensor identification..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 9, 922002 (2015)
Computer Eye SPA Based on Bidirectional Optical Interference Technology
LI Shou-rong, HU Xiang-ming, and ZHOU Qiu
To solve the problem of computer visual fatigue caused by the prolonged use of computers, a computer eye SPA was developed. The computer eye SPA applies the technology of bidirectional optical interference. The vertical light imitates natural light source of 8 000 K temperature, the transverse light absorbs the light oTo solve the problem of computer visual fatigue caused by the prolonged use of computers, a computer eye SPA was developed. The computer eye SPA applies the technology of bidirectional optical interference. The vertical light imitates natural light source of 8 000 K temperature, the transverse light absorbs the light of other bands via a eye protection spectrum card developed by a special designed micro-nano-sized material and only reflect a combination spectrum ranged in 550~700 nm. The research indicates that the subjective evaluation and the degree of satisfaction are better compared users with non-users. Objective experimental results show that the number of critical flicker fusion and blinking frequency have increased after using the computer eye SPA, the different is significant(P<0.01). It can be concluded that the computer eye SPA can adjust the external visual optical environment to relieve computer visual fatigue..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 9, 922003 (2015)
Continuous Microstructure Etching Process Polyimide Based Moving Mask Exposure
XIE Yu-ping, WU Peng, YANG Zheng, YIN Shao-yun, DU Chun-lei, and DONG Lian-he
The lithography etching process was developed to make the continuous surface micro-lens structure on a self-supporting polyimide (PI) thin film. The photo-resist sculpture structures were obtained by means of moving mask exposure technology firstly, and then they were transferred onto a PI thin film with high-fidelity.The lithography etching process was developed to make the continuous surface micro-lens structure on a self-supporting polyimide (PI) thin film. The photo-resist sculpture structures were obtained by means of moving mask exposure technology firstly, and then they were transferred onto a PI thin film with high-fidelity. While the key point of our process is how to achieve equal ratio etching. The affection of optimization of etching gas composition、ratio and flow to the equal ratio etching was studied respectively. Under the condition of some process parameters are fixed (such as the RF power, chamber pressure and self-bias), when the content of O2 was a constant in the mixing work gas of O2+SF6, with the percentage of SF6 increasing to 13.04%, and the total flow was the optimal value of 46sccm, which makes the etching rate is 136nm/min and the etching ratio is 1∶1.02. The anisotropic etching with the 2.3% etching error was obtained finally. It has proved that the micro-lens array fabricated on a PI thin film has the same optical performance comparing to a micro-lens array on a quartz substrate, by using the focal spot testing setup in our lab..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 9, 922004 (2015)
A Tunable Microwave Photonic Filter Based on Phase Modulation and Photonic Crystal Fiber Sagnac Loop
CAO Ye, CHEN Lei, and TONG Zheng-rong
A microwave photonic filter based on photonic crystal fiber Sagnac loop was presented, the filter′s center frequency can be continuously tunable. The length of photonic crystal fiber is 5m, using the thermo-sensitive liquid of Cat.19340 to fill one big hole of photonic crystal fiber and then embed it into Sagnac loop. A microwave photonic filter based on photonic crystal fiber Sagnac loop was presented, the filter′s center frequency can be continuously tunable. The length of photonic crystal fiber is 5m, using the thermo-sensitive liquid of Cat.19340 to fill one big hole of photonic crystal fiber and then embed it into Sagnac loop. The effect of different duty ratios to the period of comb spectra of Sagnac loop and the tuning range of the passband center frequency of the filter were analyzed. The measured results show that the larger the duty ratio, the smaller the period of comb spectra of Sagnac loop and the larger tuning range of the passband center frequency of the filter. In the case of the maximum duty ratio, the simulation measured period of comb spectra of Sagnac loop at the temperature of 20℃ and 80℃ are 0.72 nm and 0.52 nm respectively. Using the Sagnac loop to slice the broadband light source, by adjusting the thermo-sensitive liquid′s temperature from 20℃ to 80℃, the center frequency of the microwave photonic filter can be tuned continuously within the range of 15.5 GHz ~21.5GHz..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 9, 923001 (2015)
Error Analysis of Three FOVs Celestial Positioning and Orientation with Minimum Loss Function
WANG Hao-jing, WANG Jian-li, WU Liang, and LI Zheng-wei
The influence of each error source on the position and orientation determination accuracy in three fields of view celestial positioning and orientation method based on minimum loss function was researched. Firstly, the mathematical model of celestial positioning and orientation of three fields of view based on the miniThe influence of each error source on the position and orientation determination accuracy in three fields of view celestial positioning and orientation method based on minimum loss function was researched. Firstly, the mathematical model of celestial positioning and orientation of three fields of view based on the minimum loss function was proposed. Secondly, the characteristic and the probability distribution of error source were summarized, the impact of error sources on positioning and orientation information pair was analyzed. Finally, the position and orientation error simulation model was established, and the error simulation was done by using Monte Carlo method. The simulation results show that the mean of position accuracy is 88.1 m, and the mean of orientation accuracy is 3.0″. We point out that dominant error source is horizontal measurement error, and next one is vertical deviation data error. Outdoor experiments show that the mean of positioning accuracy is 163.0 m, the mean of orientation accuracy is 3.5″, and the horizontal measurement error is the main influence on the overall result..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 9, 923002 (2015)
The Simulation and Experimental Study of Drawing Process of Fused Fiber Coupler
MIAO Pei-pei, ZHU Yi-qing, WANG Jun, TAO Xing-chen, and YAO Xiao-tian
Based on the gradient characteristic of taper of optical fiber and the change of degree of fusion between two fibers of fused fiber coupler in the drawing process, the changing model of waveguide structure of optical fiber coupler was constructed. The relationship between optical power and stretching length was obtaineBased on the gradient characteristic of taper of optical fiber and the change of degree of fusion between two fibers of fused fiber coupler in the drawing process, the changing model of waveguide structure of optical fiber coupler was constructed. The relationship between optical power and stretching length was obtained, and optical field distribution during drawing process was gotten by numerical simulation with beam propagation method. The simulation and experimental results show that hydrogen flow and drawing speed have an influence on degree of fusion. Large hydrogen flow and low speed make degree of fusion large. The coupling effect between fibers is related to the stretching length and the degree of fusion. Long stretching length and large degree of fusion make coupling effect strong. When the stretched length is short, the coupling of taper region can be ignored. On the one hand, it’s revealed fibers become thinner and coupling effect becomes stronger in taper region with the increasing of stretched length. On the other hand it is also showed that the energy leaks out of the fiber and it leads to excess loss..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 9, 923003 (2015)
A Large Area and Low Loss Thin-Film Terahertz Polarizer
Mao Hongyan, Xu Hongmei, Xia Liangping, Wang Sijiang, Rao Xianhua, Li Wei, Shen Jun, Wei Dongshan, Zhao Guozhong, Cui Hongliang, and Du Chunlei
Polymer membrane with quality control on the silicon surface was synthesised, where the hard silicon was used as supportive substrate. The periodically metallic structures were patterned on the polymer film surface by normal photolithography. Finally, polymer film is peeled off from supportive silicon substrate. A largPolymer membrane with quality control on the silicon surface was synthesised, where the hard silicon was used as supportive substrate. The periodically metallic structures were patterned on the polymer film surface by normal photolithography. Finally, polymer film is peeled off from supportive silicon substrate. A large area and high uniformity of micro structures thin-film terahertz device has been obtained. A terahertz polarizer on polymide film substrate was fabricated using this method. Experimental results show that the polarization extinction ratio is more than 50dB at 0.1THz. The average transmittance reaches 89.78% in the polarization direction at the range of 0.1-2THz. The degree of polarization is over 99.84%. The polarization uniformity of the polarizer is fine around the diameter region of 42.3 mm. So, the flexible terahertz polarizer fabricated here is satisfied with practical demand..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 9, 923004 (2015)
Transmission through Subwavelength Metallic Annular Aperture Arrays by Excitation Mechanism of Magnetic Resonance
GUO Ya-dong, YUAN Zong-heng, YUAN Yu-yang, WANG Sheng, and XIONG Xian-ming
To design high performance terahertz filters, the optical properties of the subwavelength metallic coaxial aperture arrays were investigated. The characteristics of transmission spectra were simulated by the electromagnetic field simulation software. With the change of the geometrical parameters of the structure, two dTo design high performance terahertz filters, the optical properties of the subwavelength metallic coaxial aperture arrays were investigated. The characteristics of transmission spectra were simulated by the electromagnetic field simulation software. With the change of the geometrical parameters of the structure, two different transmission peaks appeared. One transmission peak redshifts with the increase of the outer radius or the inner radius of the air annulation, and the influence of the thickness on this peak can be neglected. Another transmission peak moves toward long wavelength with the increase of the out radius of the annulation, or the inner radius, or the thickness. This paper also provides an explanation of the phenomena by means of the localized magnetic polaritons and guided mode resonance based on the distribution of the surface current. According to the magnetic plasmon resonance, the equivalent circuit model of the metamaterial for the incidences of the transverse electromagnetic wave were set up, the effects of geometric parameters and lateral displacement on the resonance conditions were studied by this model. The variation of the array geometry parameters changes the capacitance and inductance of the equivalent circuit, which leads to the shift of the magnetic resonance peak. Comparison of the result of simulation with that of the equivalent circuit model shows that the equivalent circuit models could be useful for structure design and performance analysis of the metamaterial terahertz filters..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 9, 923005 (2015)
The Study of Dynamics Properties of Entanglement of Two Interacting Atoms Coupled to Markovion and Non-Markovion Environment
LIAO Qing-hong, XU Juan, YAN Qiu-rong, LIU Ye, and CHEN An
The entanglement dynamics of two interacting qubits under the influence of Markovian environment and non-Markovian environment was examined by making use of the linear entropy. The effect of the strength of the dipole-dipole interaction and the detuning between the transition frequency of the atom and the center frequeThe entanglement dynamics of two interacting qubits under the influence of Markovian environment and non-Markovian environment was examined by making use of the linear entropy. The effect of the strength of the dipole-dipole interaction and the detuning between the transition frequency of the atom and the center frequency of the reservoir on the time evolution of entanglement was discussed. It is shown that linear entropy decreases with the increase of the strength of the dipole-dipole interaction and the detuning between the transition frequency of the atom and the center frequency of the reservoir. Linear entropy tends to steady state within a short time in the Markovian environment, but in the non-Markovian environment linear entropy shows oscillatory behavior with the time evolution..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 9, 927001 (2015)
Quantum Discord in The System of W-like States Atoms Interacting with Three Coupled Cavities Connected by Two Optical Fibers
QIU Chang-dong, and LU Dao-ming
The Geometrical Quantum Discord (GQD) is an effective measure of quantum correlation in quantum systems. The system of W-like states atoms interacting with three coupled cavities connected by two optical fibers was investigated. In the case of like-W state, optical cavities and fiber field are all in vacuum state initiThe Geometrical Quantum Discord (GQD) is an effective measure of quantum correlation in quantum systems. The system of W-like states atoms interacting with three coupled cavities connected by two optical fibers was investigated. In the case of like-W state, optical cavities and fiber field are all in vacuum state initially. The evolution of the state vector of the system is given. GQD is adopted to quantify the degree of quantum discord between atoms. The GQD dynamics between atoms are discussed. The influences of coupling constant between cavity and fiber on geometrical quantum discord between atoms are discussed. The results show that GQD between atoms is strengthened with increasing of coupling constant between cavity and fiber..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 9, 927002 (2015)
Quantum Entanglement of a Two-Mode Field Interacting with a Cascade Three-level Atom without Rotating Wave Approximation
CONG Hong-lu, CHENG Shuang, LIU Xue-hua, YU Na, and REN Xue-zao
The quantum entanglement of the two mode coherent field interacting with a cascade three-level atom was calculated accurately with non-rotating wave approximation by using the complete quantum theory. The influences of the superposition between different atomic energy level at the initial time and the mean photon numbeThe quantum entanglement of the two mode coherent field interacting with a cascade three-level atom was calculated accurately with non-rotating wave approximation by using the complete quantum theory. The influences of the superposition between different atomic energy level at the initial time and the mean photon number on quantum entanglement evolution were considered. The results obtained by the numerical method show that the period of the quantum entanglement evolution becomes longer with the increase of the mean photon number when the atom initially at the single energy level, the quantum entanglement at the first few periods is reduced notably due to the fact of the atom is initially in the superposition state, it takes longer time for the entanglement to reach the maximum value with the increase of the mean photon number, moreover, because of the atom is initially in the superposition state, the periodic disappears. No matter which atom state, the quick oscillation due to the virtual photon process increases with the increasing of the mean photon number..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 9, 927003 (2015)
Discrimination and Characterization of Nutrient Substance in Corn Pollen Using Fourier Transform Infrared Spectroscopy
SHI You-ming, LI Dong-yu, and YI Shi-lai
To investigate the protein, polysaccharide and other nutrient substance in corn pollen, Fourier transform infrared spectroscopy combined with curve-fitting analysis was used to investigate two species of hybrid corn pollen, which called Quchen-9 and Jingfeng-3. The Fourier transform infrared spectra of corn pollen presTo investigate the protein, polysaccharide and other nutrient substance in corn pollen, Fourier transform infrared spectroscopy combined with curve-fitting analysis was used to investigate two species of hybrid corn pollen, which called Quchen-9 and Jingfeng-3. The Fourier transform infrared spectra of corn pollen presented the characteristic absorption bands of protein and polysaccharide obviously. The peaks at 1 653 cm－1, 1 546 cm－1 and 1 241 cm－1 were assigned to amide-I band, amide-II band and amide-III band respectively, which come from protein of corn pollen. The peaks at 1 078 cm－1, 1 056 cm－1, 1 030 cm－1 and 995 cm－1 were characteristic absorption bands of pollen polysaccharide. Compared with these characteristic absorption bands at the spectra of Quchen 9 and Jingfeng 3, there were obvious differences between the two species of corn pollen. It indicated that the concentration of protein and polysaccharide in corn pollen had difference between the species of Quchen-9 and Jingfeng-3. Fourier self-deconvolution and second derivative of the 1 900~950 cm－1 band was followed by curve-fitting analysis to generate the underlying multi-component peaks. The relative area percentages of multi-component peaks showed that the polysaccharide content in the corn pollen of Quchen-9 was higher than that of the Jingfeng-3. However, the relationship of protein content was reverse. The present results suggest that Fourier transform infrared spectroscopy is a promising method to identify nutrient substance in corn pollen..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 9, 930001 (2015)
High Time Resolved Transient Spectrum Detection Technique Based on Area CCD
JIN Jing, BAI Yong-lin, YANG Wen-zheng, ZHU Bing-li, WANG Bo, and GOU Yong-sheng
To raise the scan rate of CCD and apply to the hundred nanosecond scale transient phenomena detection, a transient spectrum detection method with high time resolution was proposed and demonstrated by experiment, based on area CCD. By reforming time sequence of CCD and utilizing principle of frame restore, detection witTo raise the scan rate of CCD and apply to the hundred nanosecond scale transient phenomena detection, a transient spectrum detection method with high time resolution was proposed and demonstrated by experiment, based on area CCD. By reforming time sequence of CCD and utilizing principle of frame restore, detection with high time resolution was achieved. LED impulse light experiment was performed to demonstrate feasibility of the method. Experiment results show that this transient phenomena acquisition method based on area CCD is efficacious. Detection frame rate can be as high as 10 Mfps. Time resolution is less than 100 ns, and can be able to image 2 048 frames continuously. The experiment is of importance to expand application of CCD in the transient spectrum detection area..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 9, 930002 (2015)
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