Journals >Acta Photonica Sinica
Contents
2018
Volume: 47 Issue 9
35 Article(s)
Export citation format
Relativistic Effects in 2p Photoionization from the Excited States of Sodium Atoms
LIU Xiao-bin, SHI Ying-long, XING Yong-zhong, LU Fei-ping, LI Xiang-bing, WANG Yu-ping, and HU Hong-wei
Based on the multi-configuration Dirac-Fock method, 2p photoionization process of sodium atoms from the initial state 2p63p were investigated at a photon energy of 54 eV. Usually the relativistic effect has very obvious influence on atomic photoionization process. The influence of relativistic effects on the photoionizBased on the multi-configuration Dirac-Fock method, 2p photoionization process of sodium atoms from the initial state 2p63p were investigated at a photon energy of 54 eV. Usually the relativistic effect has very obvious influence on atomic photoionization process. The influence of relativistic effects on the photoionization thresholds is negligible, but it can produce substantial change in the intensity distribution in photoelectron spectra, so that the spectra structures from the initial states 2p63p(2P1/2,3/2) are completely different. In the nonrelativistic limit, as generally expected, the spectra structures from the two states are almost identical. Furthermore, this study demonstrates the information that may be obtained regarding the relativistic effects in the photoionization processes from excited states..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 9, 902001 (2018)
Method of Object Pose Measurement Based on Single PSD
HUANG Zhan-hua, ZHANG Ya-nan, FANG Shi, and CAI Huai-yu
A pose measurement method based on single position sensitive detector was proposed in order to overcome the limitation of image sensor response and precision and the defect of corresponding image processing algorithm. First, a coordinate system was established while the origin was based on detector photosensitive surfaA pose measurement method based on single position sensitive detector was proposed in order to overcome the limitation of image sensor response and precision and the defect of corresponding image processing algorithm. First, a coordinate system was established while the origin was based on detector photosensitive surface center and space attitude angle was defined in this coordinate system. Then eight infrared LED light sources of plane object glowed in circle were defined as detecting target and they were imaged on the active area of the positive sensitive detector via optic system. After the electricity digital signal had been processed by the program, using two-dimensional image coordinate of feature points and specific relative position relation of light sources, the position and attitude information of object in sensor coordinate system would be gained finally. Before the measurement experiment, the stability of the system was verified. Experimental results show that measurement distance of this method is 10 m in the depth direction within the detectable field angle of 16.3° while the maximum absolute error is 36.2 mm. The maximum position measurement mean absolute deviation in other direction is 7.1 mm and angle measurement error is higher than 2°. This method is simple while real-time frequency of measurement could achieve 100 Hz and it could meet the real-time requirements in pose measurements commendably..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 9, 904001 (2018)
Experimental Analysis of Pulse Signal Detection Capability of the MCP X-ray Detector
ZHOU Qing-yong, SHENG Li-zhi, WEI Zi-qing, LIU Si-wei, CHEN Chen, JI Jian-feng, REN Hong-fei, MA Gao-feng, ZHANG Cai-hong, and SUN Peng-fei
For analyzing the X-ray pulsed signal observation capability of micro-channel plate detector, a long-time experiment of micro-channel plate detectors under different radiation flux and different background noise was operated on the X-ray detector ground testing system. Meanwhile, a set of evaluation methods of pulse obFor analyzing the X-ray pulsed signal observation capability of micro-channel plate detector, a long-time experiment of micro-channel plate detectors under different radiation flux and different background noise was operated on the X-ray detector ground testing system. Meanwhile, a set of evaluation methods of pulse observation capability of X-ray detectors were established, the expressions of the signal-to-noise ratio, the correlation of pulse profile, the measurement accuracy of pulse arrival time, the minimum detectable power were derived based on the photon counting model. 8 groups of 10 000 s X-ray photon time-of-arrival dataset were received by the 20 cm2 micro-channel plate detectors. Then the effective observation data were dealt with, the pulse period of each dataset was gained, the observable pulse profile was replicated, and their characteristic parameters were estimated. The experimental result shows that the micro-channel plate detector has a good capability of X-ray pulse signal observation and reconstruction, the signal-to-noise ratio, the correlation of pulse profile, the measurement accuracy of pulse arrival time of the observed pulse profile are 35.73, 88.38%, 51.53 μs at the low pulse signal flux (the X-photon flux density is 0.05 ph/cm2/s), while those are 35.73, 88.38%, 51.53 μs at strong background noise(the background noise is 16 times the intensity of the pulse signal). This result has revealed that the micro-channel plate detector has the observation ability of a certain faint X ray pulsar. The pulse detection capability of micro-channel plate detector is improved with the increase of the intensity of the pulse signal, the decrease of the background noise intensity and the increase of the accumulated observation time..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 9, 904002 (2018)
Echo of the Optical Imaging System under Different Extent of Damage to CCD
ZHANG Ming-xin, NIE Jin-song, DOU Xian-an, and SUN Ke
The cat′s eye echoes model of the optical imaging system under different damage conditions was established and the influence of the damage to the charge coupled device layers on the cat′s eye echo power was analyzed. Based on this, the corresponding relationship between the echo power of the cat's eye and the damagThe cat′s eye echoes model of the optical imaging system under different damage conditions was established and the influence of the damage to the charge coupled device layers on the cat′s eye echo power was analyzed. Based on this, the corresponding relationship between the echo power of the cat's eye and the damage degree of the CCD was established and verified by experiments. The results show that the field intensity is the strongest in the center of cat′s eye echo which is from imaging optics system, and the power of the echo increases dramatically and then decrease steeply and decrease slowly with the damage degree more serious. The damaged status of CCD can be judged according to this rule. The study results have certain reference value for monitoring the damage degree of CCD in real time in the far field..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 9, 904003 (2018)
Usage of Additive for the Improvement of the Filling Effect during Filling the Grating Structure of the Nanoimprint Stamp
ZHENG Yong-guang, ZHANG Ran, LIU Ze, and CHU Jin-kui
In order to improve the voids phenomenon during filling the high-aspect-ratio nanograting structures using electroforming process, this paper uses the electrostatic adsorption principle of Janus green B molecule to eliminate the process defect by adding the leveling agent JGB to the electroforming bath. This paper compIn order to improve the voids phenomenon during filling the high-aspect-ratio nanograting structures using electroforming process, this paper uses the electrostatic adsorption principle of Janus green B molecule to eliminate the process defect by adding the leveling agent JGB to the electroforming bath. This paper completes the replication of nickel nanoimprint stamp on the flexible substrate via nanoimprint technology and electroforming process. In this process, the nanograting structures on the master silicon stamp are transferred to a polymer substrate using the hot embossing process to obtain soft template for embossing firstly; then, a seed layer of nickel is deposited on the polymer substrate nanostructure surface using sputtering process. The nanograting sructures are filled and the back plane of the replic is electroformed by electroforming process. Finally, the electroformed part and polymer are separated. Based on this process, a nickel nanoimprint stamp with six nano-grating areas of 1.3 mm×1.3 mm size, 201 nm pitch, 98 nm linewidth and 104 nm depth was replicated successfully. Compared with silicon master stamp, the error of the replicated stamp′s feature size is whthin 5%, the result shows good correlation between the dimensions of the replicated stamp′s features and the corresponding master stamp′s features. The pitch of the replicated stamp with grating structures has no error, the error of the linewidth is whthin 2% after hot-pressing process, the test result demonstrate that the mechanical strength of the replica is sufficient for the hot embossing process..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 9, 905001 (2018)
Design for the Phase-only FAN-OUT Grating of Orbital Angular Momentum Separation System
YIN Xiao-li, LIAO Huan-yu, WANG Yong-jun, CHANG Huan, CUI Xiao-zhou, and LIN Jiao-ling
Based on the coordinate-transformation Orbital Angular Momentum (OAM) sorting scheme, this paper designs a phase-only FAN-OUT grating using a method based on iterative algorithm to copy beams and improve the resolution of the OAM beams sorting efficiently. This paper establishes a numerical simulation model for high-reBased on the coordinate-transformation Orbital Angular Momentum (OAM) sorting scheme, this paper designs a phase-only FAN-OUT grating using a method based on iterative algorithm to copy beams and improve the resolution of the OAM beams sorting efficiently. This paper establishes a numerical simulation model for high-resolution sorting of OAM beams. Numerical results indicate that the energy in the spot received by the system with phase-only FAN-OUT grating is more concentrate and the minimum reduction of dispersion degree of the OAM spectrum is 0.35, the minimum reduction of the error probability is 15%. The phase-only FAN-OUT grating is advantageous for realizing high-resolution sorting of OAM beams..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 9, 905002 (2018)
Adaptive Model Update via Fusing Peak-to-sidelobe Ratio and Mean Frame Difference for Visual Tracking
XIONG Chang-zhen, CHE Man-qiang, WANG Run-ling, and LU Yan
In order to adapt the correlation filter model to the change of the target appearance and improve the robustness and real-time performance of the correlation filter algorithm for visual tracking, an adaptive learning rate adjustment method for real-time tracking of a single-layer convolution filter is proposed, which iIn order to adapt the correlation filter model to the change of the target appearance and improve the robustness and real-time performance of the correlation filter algorithm for visual tracking, an adaptive learning rate adjustment method for real-time tracking of a single-layer convolution filter is proposed, which is based on the relationship of the correlation filter response value, mean frame difference and the object movement displacement. This method selects the convolution features of a single convolution layer to train the correlation filter classifier that is used to predict the position of object, reducing the convolution feature dimension and improving the speed of visual tracking. Meanwhile it uses the fast-scale prediction method to estimate the object's scale, and adopts a sparse model update strategy. Besides, the Peak-to-Sidelobe Ratio (PSR) of convolutional response is used to estimate the credibility of the predicted location. The apparent change of the object is evaluated by combining the mean frame difference and the object movement displacement. And the learning rate of the correlation filter model update can be adjusted by these two terms adaptively, so that the change characteristics of the object can be quickly learned. The accuracy of visual tracking is improved by this method. The method is tested on the standard OTB-100 dataset. The results show that the average distance accuracy is 90.1%, which is better than the state-of-the-art algorithms in the experiment. And the average success rate is 79.2%, which is only smaller than the continuous convolution tracking algorithm(CCOT). But the average speed is 31.8 frames per second, nearly 30 times of the CCOT..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 9, 910001 (2018)
Infrared and Visible Image Fusion Based on Sparse Feature
DING Wen-shan, BI Du-yan, HE Lin-yuan, FAN Zun-lin, and WU Dong-peng
Since the object information can not be extracted efficiently by the traditional infrared and visible image fusion algorithms, an infrared and visible image fusion method based on the non-subsampled shearlet transform and sparse structure features is proposed. Firstly, the source images are decomposed by the non-subsamSince the object information can not be extracted efficiently by the traditional infrared and visible image fusion algorithms, an infrared and visible image fusion method based on the non-subsampled shearlet transform and sparse structure features is proposed. Firstly, the source images are decomposed by the non-subsampled shearlet transform. Then, benefit from the advantage of principal component analysis on extracting edge and contour significant features, the fusion rule in low-frequency sub-bands coefficients are merged by using the principal component analysis-based approach. Afterwards, the sparseness based on structural information guides the fusion of high frequency subband coefficient. Finally, the inverse non-subsampled shearlet transform is employed to obtain the fused image. The experimental results demonstrate that the proposed method preserves the background information on visible image and highlights the structural information on infrared image, and improves fusion results effectively..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 9, 910002 (2018)
Design and Experimental Study of ICCD Gated Pulse Source
HU Jun-yu, PEI Cheng-quan, TIAN Jin-shou, WANG Jun-feng, FANG Yu-man, and WEN Wen-long
Based on the microprocessor and combined with analog delay circuit and digital logic circuit, a strobe pulse source with a resolution of 5 ns, a minimum pulse width of 65 ns, a frequency up to 1 MHz, and remote control by the host computer is designed. Using this pulse source in combination with a gate power supply, thBased on the microprocessor and combined with analog delay circuit and digital logic circuit, a strobe pulse source with a resolution of 5 ns, a minimum pulse width of 65 ns, a frequency up to 1 MHz, and remote control by the host computer is designed. Using this pulse source in combination with a gate power supply, the gated shutter time of the ICCD coated with a metallic conductive substrate and no metallic conductive substrate on the cathode are tested. The results show that the ICCD has a shorter turn-on time when metal substrates are plated. The corresponding equivalent circuit model and the RC equivalent equation which the opening and closing process of photocathode met are established, qualitative analysis shows that the decrease in the cathode surface resistance is the main factor to shorten the ICCD open time..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 9, 911001 (2018)
Checkout of External Trigger Delay in Linear Image Acquisition System
MA Wei-hong, TIAN Hui, DONG Tao, and NI Jin-ping
Aiming at effective external trigger of high speed linear image acquisition system in practical application, a trigger delay checkout method was presented, for setting the trigger correctly and getting dynamic target image reliably. A double screens device is used to obtained velocity of dynamic target, the second screAiming at effective external trigger of high speed linear image acquisition system in practical application, a trigger delay checkout method was presented, for setting the trigger correctly and getting dynamic target image reliably. A double screens device is used to obtained velocity of dynamic target, the second screen provide trigger signal to linear image acquisition system, the time that system received trigger signal is computed according to target velocity and screens parameters; the time that system start to capture is computed by analysis of sequence linear image captured by system, then trigger delay is checked out. For a specific type linear image acquisition system with 64 000 line per second (lps), trigger delay is measured, the test results analysis show that the linear image acquisition system has external trigger delay, the average delay time is 152 μs, the delay variance is 3.3 μs, and the delay error is less than 1 line scan cycle. The factors leading to measurement errors and action principle are analysed, and a common method to design measurement system parameters are presented by two external trigger delay measurement precision analysis examples of line scan camera with 10 000 lps and 50 000 lps line scan frequence..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 9, 911002 (2018)
Low Side Lobe On-chip Two Dimensional Optical Phased Array Based on the Hill Climbing Algorithm
DU Shu-jian, ZHANG Ling-xuan, WANG Guo-xi, LI Zhong-yu, ZHANG Qi-hao, XIE Peng, LI Yan, MI Lei, SUN Xiao-chen, and ZHANG Wen-fu
A two-stage directional coupler structure is proposed to realize the two dimensional optical phased array, and a distinctive C-bend waveguide is designed for thermal regulation as optical phase shifter of array element. A method that compresses far field side lobes caused by high-order interference for sparse on-chip oA two-stage directional coupler structure is proposed to realize the two dimensional optical phased array, and a distinctive C-bend waveguide is designed for thermal regulation as optical phase shifter of array element. A method that compresses far field side lobes caused by high-order interference for sparse on-chip optical phased arrays is presented. Hill climbing algorithm is adopted to optimize the uniform antenna spacing and make it become non-uniform, which will greatly mitigate constructive interference conditions and then compress far field side lobes. Using finite-difference time-domain method to simulate the sparse optical grating coupler array designed at 1 310 nm wavelength showing that this optimization can realize a -6～-7 dB ratio of side lobe and main lobe..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 9, 913001 (2018)
Design and Fabrication of Photoconductive Mesh on Transparent Substrate
WANG Jun, LENG Yan-bing, SUN Yan-jun, JI Xue-song, WANG Li, and WANG Yue
Based on the semiconductor photoconductive effect, the mechanism of photo-induced conductive composite mesh was analyzed, and the design ideas and structural characteristics of the photo-induced conductive composite mesh were clarified. Combined with the transparent sapphire substrate, the radar wave 2~18 GHz and infraBased on the semiconductor photoconductive effect, the mechanism of photo-induced conductive composite mesh was analyzed, and the design ideas and structural characteristics of the photo-induced conductive composite mesh were clarified. Combined with the transparent sapphire substrate, the radar wave 2~18 GHz and infrared 3~12 μm wavebands were selected as the research object to optimize and simulate the parameters of the composite mesh structure. When the period of mesh parameter cycle changes from 5 mm to 2.5 mm, and the side length changes from 4.9 mm to 2.4 mm , correspondingly, the central resonance frequency of the mesh changes from 13.2 GHz to 14 GHz. The principle of coaxial alignment of diffraction gratings was used to ensure the alignment accuracy of the two lift-off lithography processes. The mesh cycle error is less than 6 μm and the length error is less than 5 μm, which satisfies the experimental requirements. The optical and electrical properties of the composite mesh were tested, and the results are: compared the sample without sapphire substrate with the composite mesh, the overall trend of the infrared transmittance curve did not change, and the overall transmittance decreased by about 7.8%, which is a 3.4% difference from the single metal mesh. This is in line with the law of infrared transmission loss. The central resonant frequency of the composite mesh measured at a sensitive wavelength of 600 nm is changed from 13.22 GHz to 14.03 GHz, which is basically consistent with the simulation results. Thus, the feasibility of illumination to control the electromagnetic performance of the composite grid was verified..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 9, 913002 (2018)
Ultra-wide Two-dimensional Beam Steering by Silicon Integrated Optical Phased Array
LI Zhong-yu, ZHANG Ling-xuan, ZENG Chao, DU Shu-jian, GE Zhi-qiang, XIE Peng, ZHANG Qi-hao, WANG Guo-xi, SUN Xiao-chen, MI Lei, and ZHANG Wen-fu
An alternative approach to realize 2D beam steering with ultra-wide range by silicon integrated optical phased array is proposed. A dot matrix scanning method, using the phase control and grating emitters with different periods, is conceived to design the optical phased array device without the requirement of tunable lAn alternative approach to realize 2D beam steering with ultra-wide range by silicon integrated optical phased array is proposed. A dot matrix scanning method, using the phase control and grating emitters with different periods, is conceived to design the optical phased array device without the requirement of tunable lasers. Simulations demonstrate an ultra-wide steering range up to 120°×100°, together with over 16×400 resolvable points by using a single-wavelength laser. Moreover, the designed optical phased array device demands only a part of active elements working simultaneously, which benefits to reduce the electrical power consumption. The proposed approach provides a promising solution for wide-angle, low-cost, and low-power consumption 2D beam steering devices, especially suitable for solid-state light detection and ranging systems..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 9, 913003 (2018)
Passively Mode-locked Ytterbium-doped Fiber Laser Based on MoO3 as Saturable Absorber
JIANG Jun-lin, YUE Wen-jie, WANG Wei-qi, DING Yi-chen, WU Bo, and SHEN Yong-hang
A MoO3 saturable absorber based on Yb-doped mode-locked fiber laser which can operate in both continuous wave and Q-switched mode-locked regimes was reported. A stable continuous wave mode-locked pulse train at a repetition rate of 17 MHz was achieved by using a ring cavity configuration at 95 mW incident pump power, tA MoO3 saturable absorber based on Yb-doped mode-locked fiber laser which can operate in both continuous wave and Q-switched mode-locked regimes was reported. A stable continuous wave mode-locked pulse train at a repetition rate of 17 MHz was achieved by using a ring cavity configuration at 95 mW incident pump power, the pulse width, central wavelength and 3 dB spectral bandwidth are 130 ps, 1 067.06 nm and 0.27 nm. Stable Q-switched mode-locked pulse train occurred at 280 mW incident pump power. As the pump power varied from 280 mW to 400 mW, the repetition rate of Q-switched envelope varied from 26.51 to 48.7 kHz, and the width of Q-switched envelope varied from 14.6 μs to 4.1 μs, the pulse width and the central wavelength remained invariant. The 3 dB spectral bandwidth was 0.62 nm..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 9, 914001 (2018)
Sub-10-fs Ti∶sapphire Oscillator Pumped by Picosecond Laser
HE Hui-jun, JIANG Jian-wang, CHENG Meng-yao, SONG Jia-jun, WANG Zhao-hua, FANG Shao-bo, and WEI Zhi-yi
A high-power Nd: YVO4 picosecond laser was developed, and the continuously mode-locking with output power of 6 W was realized under 15 W 808 nm pump power, corresponding to optical-to-optical conversion efficiency of 40%. The picoseond laser was amplified to 14 W by a single segment amplifier stage. After frequency mulA high-power Nd: YVO4 picosecond laser was developed, and the continuously mode-locking with output power of 6 W was realized under 15 W 808 nm pump power, corresponding to optical-to-optical conversion efficiency of 40%. The picoseond laser was amplified to 14 W by a single segment amplifier stage. After frequency multiplication, 7 W picosecond laser was obtained, serving as pump source of Ti∶sapphire oscillator. Being pumped by 4.5 W 532 nm picosecond laser, the pulse trains output with pulse duration compressed to 9.4 fs and average power of 150 mW was obtained. By tuning the cavity length of the Ti: sapphire oscillator to decrease the difference between the two oscillators′ cavity length, self-initiating Kerr-lens mode-locking was realized. The result shows that the picosecond laser pumping could trigger the Ti∶sapphire oscillator mode-locking and output femtosecond pulse trains..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 9, 914002 (2018)
Etching Process of 980 nm Tapered Semiconductor Laser
QIAO Chuang, SU Rui-gong, FANG Dan, TANG Ji-long, FANG Xuan, WANG Deng-kui, ZHANG Bao-shun, and WEI Zhi-peng
In order to solve the problems of bad sidewall steepness and device repetition in the traditional etching process of semiconductor laser, the etching process of 980 nm tapered semiconductor laser is optimized by means of the combination of wet etching and dry etching. The difference of wet etching solution and concentrIn order to solve the problems of bad sidewall steepness and device repetition in the traditional etching process of semiconductor laser, the etching process of 980 nm tapered semiconductor laser is optimized by means of the combination of wet etching and dry etching. The difference of wet etching solution and concentration ratio is determined through the study of mesa roughness and etching speed. The effect of inductively coupled plasma etching on the surface morphology of the damaged grooves in ridged waveguide and cavity is analyzed. The results show that the etching rate is about 7 nm/s, and the etching rate is easy to be controlled by wet etching with the ratio of NH3 ·H2O∶H2O2∶H2O=1∶1∶50. The surface of the sample has good roughness and uniformity, the ridge waveguide and cavity etched by inductively coupled plasma have good steepness of the side wall of the groove, and there is no transverse drilling erosion..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 9, 914003 (2018)
Experimental Study on the Dual-wavelength Laser Based on the Nd∶YVO4/Nd∶GdVO4 Combined Crystal
HAN Ning, HU Miao, LI Peng, JIN Tao, FENG Bing, OU Jun, ZHOU Xue-fang, YANG Guo-wei, LU Yang, and BI Mei-hua
A Dual-Wavelength Laser (DWL) based on the Nd∶YVO4/Nd∶GdVO4 combined crystal was presented. The thermal effect and the frequency-separation tuning mechnism of the DWL were investigated. In the experiments, with fixed pumping power, when the heat sink temperature of the combined crystal increased from 5 ℃ to 40 ℃, the fA Dual-Wavelength Laser (DWL) based on the Nd∶YVO4/Nd∶GdVO4 combined crystal was presented. The thermal effect and the frequency-separation tuning mechnism of the DWL were investigated. In the experiments, with fixed pumping power, when the heat sink temperature of the combined crystal increased from 5 ℃ to 40 ℃, the frequency separation of the DWL signal decreased from 351.1 GHz to 316.1 GHz, the frequency separation decreasing rate was measured as -0.95 GHz/℃. For the experimental results, it was found that the wavelength shifting of the DWL signal is mainly caused by the Emission Cross Section (ECS) spectra shifting of the laser crystals with the temperature varying, and the change of the frequency separation is caused by different ECS spectral shifting rates of the crystals. The analysis results are in good agreement with the experimental results..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 9, 914004 (2018)
Timing Jitter in Pulsed Injection Locking of a Passively Mode-locked Semiconductor Laser
XU Yu-lan, LIN Zhong-xi, LIN Qi, CHEN Jing-yuan, and SU Hui
The effects of injection locking on the timing-jitter noise properties of a passively mode locked semiconductor laser are investigated theoretically via a set of simplified soliton perturbation equations. We find that, with injection coupling coefficient of 10-3 ps-1, the timing-jitter noise of the slave mode-locked laThe effects of injection locking on the timing-jitter noise properties of a passively mode locked semiconductor laser are investigated theoretically via a set of simplified soliton perturbation equations. We find that, with injection coupling coefficient of 10-3 ps-1, the timing-jitter noise of the slave mode-locked laser can be reduced from a few picoseconds (3.83 ps) to a few femtoseconds in the frequency range from 100 kHz to 10 GHz. We also discuss the impacts of the steady state phase difference between the injection and slave pulses, coupling coefficient, and linewidth enhancement factor on the timing-jitter noise. Calculations show that timing jitter is insensitive to the phase difference while coupling coefficient has a strong effect on the timing jitter, and a smaller linewidth enhancement factor leads to better timing jitter performance..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 9, 914005 (2018)
Temporal Power Profiles Remote Precise Measurement of Suppressing Frequency Modulation to Amplitude Modulation Conversion
HUANG Jia-peng, FAN Wei, SHI Zhi-dong, PAN Xue, LI Rao, LU Xing-hua, WANG Xiao-chao, and ZHANG Sheng-jia
A method of remote precise measurement of laser temporal power profiles was proposed. This method used the single polarization optical fiber for laser remote transmission and combined with temporal power profile recovery algorithm where the rising edge and the top profiles of laser pulses were separated and processed rA method of remote precise measurement of laser temporal power profiles was proposed. This method used the single polarization optical fiber for laser remote transmission and combined with temporal power profile recovery algorithm where the rising edge and the top profiles of laser pulses were separated and processed respectively. The experiment of temporal power profiles remote measurement of 1 053 nm laser pulses in the front end of high power laser facility was carried out. The results show that the method effectively avoids the influence of frequency modulation to amplitude modulation on the temporal power profiles measurement, and undistorted temporal waveform after remote transmission is obtained. The calculated error introduced by this measurement method is less than 0.8% per nanosecond. The proposed method can be applied to temporal waveform remote centralized measurement in high power laser facility..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 9, 914006 (2018)
Enhancing Organic-inorganic Hybrid Perovskite Amplified Spontaneous Emission Based on the Gold Nanoparticles
WU Xiao-yan, LIU Guo-dong, LI Yang-long, LI Wei, WU Ling-yuan, FU Bo, WANG Wei-ping, ZHANG Da-yong, ZHAO Jian-heng, and CHEN Ping
When the organic-inorganic hybrid perovskite has been regarded as the gain medium in lasers, the lasing devices with nanosecond laser pulses or continuous wave pumping at room temperatures is unstable and the electrically driven lasing is difficult to be achieved. Gold nanoparticles solution and PEDOT∶PSS solution wereWhen the organic-inorganic hybrid perovskite has been regarded as the gain medium in lasers, the lasing devices with nanosecond laser pulses or continuous wave pumping at room temperatures is unstable and the electrically driven lasing is difficult to be achieved. Gold nanoparticles solution and PEDOT∶PSS solution were blended, gold nanoparticles with size of 20 nm were doped into PEDOT∶PSS interface layer in a slab waveguide device. As a result, the facile device doping with gold nanoparticles shows a 5.5-fold enhanced amplified spontaneous emission intensity than the device without gold nanoparticles. The results show that gold nanoparticles can effectively improve the absorption of CH3NH3PbBr3 film, increase the population inversion and accelerate the excitons radiative decay process. Combining with theoretical simulation, the comprehensive near- and far-field surface plasmon of gold nanoparticles could both couple with the absorption/emission area, so that the amplified spontaneous emission of planar waveguide are improved. The results can provide a reference in fabricating the high performance optically pumped amplified spontaneous emission devices..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 9, 916001 (2018)
Luminescence Properties of YAG∶Ce Phosphor Film Composite Material and pc-WLED Effected by Particle Size and Concentration
XU Sai-sai, WEI Jian-jun, YANG Liu-kun, and PAN Zhi-hua
High temperature molding technology was used to prepare YAG∶Ce phosphor film composite material with YAG∶Ce and silica gel as raw material, and the white light LED was packaged with blue LED light source. Based on the Mie theory, fluorescence spectrometer, rapid spectral radiometer and spectral distribution meter, the High temperature molding technology was used to prepare YAG∶Ce phosphor film composite material with YAG∶Ce and silica gel as raw material, and the white light LED was packaged with blue LED light source. Based on the Mie theory, fluorescence spectrometer, rapid spectral radiometer and spectral distribution meter, the color parameters of film material and white LED were calculated and measured, and the influence mechanism of the particle size and concentration on the parameters were analyzed. At the same concentration, with the decreasing of the particle size, the mean free path decrease and the scattering coefficient and probability of absorption and conversion of the excited photon in the film material increase accordingly, The emission intensity of the film material, the luminous efficiency and homogeneity of light color of white LED are all increase correspondingly, the optimum value of the particle size is 8.7 μm at the same concentration; At the same particle size, along with the increasing of the concentration. The emission intensity of the film material, the luminous flux and photochromic uniformity of the white LED are also increase correspondingly. When the concentration is 4% and particle size is 8.7 μm, the white LED color temperature is 5 514 K, the luminous efficiency is 136.8 lm/W (@300 mA, 6.6 V), value of homogeneity of light color is 0.759, color coordinates x=0.332 2, y=0.359 6, the color point is located in the positive white light area near the blackbody radiation curve, which is the best concentration. Under different currents, the luminous efficiency and efficiency of white LED are linear, luminous flux: y=0.681 6x+63.121, R2=0.995 7, luminous efficiency: y=-0.062 8x+155.2, R2=0.991 6.This study shows the feasibility of flim material in white LED applications, and the relevant laws obtained are of reference for practical applications..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 9, 916002 (2018)
Luminescent Properties of Pr3+ Doped LiYF4 Glass Ceramics for White Light-emitting Diodes
CAO Hui, ZHENG Bin, GU Zhao-feng, HU Jian-xu, and ZHANG Yue-pin
xPr3+-activated 43SiO2-23Al2O3-27LiF-17YF3 (x=0.1、0.2、0.3、0.4 ) (mol%) glass were synthesized by a conventional melting technique, and then annealed at 530℃, 540℃ and 550℃, respectively. Transparent LiYF4: Pr3+glass ceramics were successfully prepared. X-ray diffraction and transmission electron microscope were used toxPr3+-activated 43SiO2-23Al2O3-27LiF-17YF3 (x=0.1、0.2、0.3、0.4 ) (mol%) glass were synthesized by a conventional melting technique, and then annealed at 530℃, 540℃ and 550℃, respectively. Transparent LiYF4: Pr3+glass ceramics were successfully prepared. X-ray diffraction and transmission electron microscope were used to monitor the crystalline phase structure after the glass specimens were annealed at temperature increasing from 530℃ to 550℃, the average size of nanocrystals in glass ceramics was 14±4 nm. The UV-visible spectra were used to monitor the transparency remained at a high level. The spectral properties and lifetime of glass and glass ceramics were investigated. The parameters of LED also be investigated. Under 404 nm excitation, the glass ceramics which doped 0.3 mol Pr3+ion and heated at 550℃ had the highest light output intensity, when it was made into LED, it produced white light. The calculated color coordinates of the LED was located in x=0.33,y=0.35..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 9, 916003 (2018)
Preparation and Optoelectronic Properties of Large-scale MAPbI3 Single Crystals
ZHANG Chan-chan, ZHANG Fang-hui, DING Li-ping, ZHU Xiao-ting, and LI Rong-jin
A large size (about 150 μm) high quality MAPbI3 single crystals have been grown by modifying the surface of the substrate to control the nucleation position. Furthermore, the growth factors of PbI2 crystals was studied systematically, mainly including substrate temperature, flow rate of carrier gas, time effect. The reA large size (about 150 μm) high quality MAPbI3 single crystals have been grown by modifying the surface of the substrate to control the nucleation position. Furthermore, the growth factors of PbI2 crystals was studied systematically, mainly including substrate temperature, flow rate of carrier gas, time effect. The results showed that the best conditions for the crystal growth correspond to 350 ℃, 20 sccm and 20 min. In addition, the perovskite single crystalline was measured by XRD when exposed to air for 50 days or more. Although the characteristic peaks were different in size, the crystal did not change as a whole. By analyzing the optoelectronic properties of device, we found that the switch ratio of device is up to 104, and its responsivity is 3.8×104 A/W. In addition, the device shows a fast response (rise time: 0.03 s; fall time: 0.15 s). The above shows that our developed MAPbI3 single crystal photodetector will have a very good application in the field of optoelectronics..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 9, 916004 (2018)
Study of Titanium-doped Silicon Films Prepared by Magnetron Sputtering and Nanosecond Pulsed Laser
WANG Kai, LI Xiao-hong, ZHANG Yan-bing, WEN Cai, and LIU De-xiong
An improved hyper-doping process has been developed which combines the vacuum magnetron sputtering coating and the 532 nm wavelength visible nanosecond pulse laser melting to prepare the silicon thin films of titanium doping. The characteristics of hyper-doped layer and the infrared light absorption properties of silicAn improved hyper-doping process has been developed which combines the vacuum magnetron sputtering coating and the 532 nm wavelength visible nanosecond pulse laser melting to prepare the silicon thin films of titanium doping. The characteristics of hyper-doped layer and the infrared light absorption properties of silicon thin film were studied. The X-ray photoelectron spectroscopy shows that the titanium concentration of doping layer of sample is more than 1% (the corresponding titanium atom concentration is about 5×1020 cm-3), higher than the hyper-doping concentration of titanium in silicon. And the thickness of hyper-doping layer is more than 200 nm which improves obviously compared with traditional technology. The variable range of the concentration of titanium atoms is not more than 20%, and the atom distribution is more homogeneous. The glancing incidence X-ray diffraction pattern shows that the crystallinity of the silicon thin film layer is polycrystalline structure and about 25% around after pulsed laser melting. At the same time, the infrared light absorption measurement shows that the hyper-doping silicon thin film has high infrared absorptivity in wavelength larger than 1 100 nm. The highest infrared light absorption coefficient of sample is almost to 1.2×104 cm-1, which is far more than that of monocrystalline silicon. The material has obvious characteristics of sub-band absorption and shows a donor impurity energy level of the Ec-0.26 eV. The Hall effect measurement shows that the thin film layer has high carrier concentration, over 8×1018 cm-3. The Hall effect measurement shows that the thin film layer has high carrier concentration, over 8×1018 cm-3..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 9, 916005 (2018)
Light Diffusion in Turbid Cylinder Based on Finite Element Simulation
ZHANG Shu, CHEN Si-yu, LIU Yu-hong, and TAN Zuo-jun
In this paper, we used finite element simulation to study the light diffusion in cylinder. The spatial reflectance of different optical methods was discussed in details. The results were in good agreement with that of Monte Carlo simulation. When μ′s/μa≥5, the error was less than 10% and when in the far-source zone, thIn this paper, we used finite element simulation to study the light diffusion in cylinder. The spatial reflectance of different optical methods was discussed in details. The results were in good agreement with that of Monte Carlo simulation. When μ′s/μa≥5, the error was less than 10% and when in the far-source zone, the error was even less than 5%. Besides the light penetration depths obtained from finite element simulation were also very close to the results of Monte Carlo simulation, which was only a little lower due to the diffusion approximation. The error was no more than 7% and decreasing with higher value of μ′s/μa. Moreover, finite element simulation results were more accurate than analytical solution. The error of analytical solution was about 10% in the far-source zone and more than 15% at the near-source zones. The calculation time of the three methods were also compared. For one simulation, it cost about 385 second for finite element simulation, 416 seconds for analytical solution and 8~9 hours for Monte Carlo simulation. The finite element simulation has better accuracy than analytical solution while has much faster calculation speed than Monte Carlo simulation. So it is an effective and promising method to solve light diffusion in cylinder or turbid with curvatures..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 9, 917001 (2018)
Method to Quantitate Parameter γ Related to Tissue Microstructure by Reflectance Measured at Microdomains Close to the Source
WANG Xing, LI Wen-yan, QIAO Yan-qing, and LIU Ying
A method of measuring tissue microstructure parameter γ with optical fiber probe was presented. Based on spherical fractal model of Intralipid, the diffuse reflection data of the photon through Intralipid was obtained using Monte Carlo simulation, and the function relationship between diffuse reflectance and γ was estaA method of measuring tissue microstructure parameter γ with optical fiber probe was presented. Based on spherical fractal model of Intralipid, the diffuse reflection data of the photon through Intralipid was obtained using Monte Carlo simulation, and the function relationship between diffuse reflectance and γ was established by non-linear fitting of the data. Research shows that the diffuse reflectance is linearly related to the dimensionless reduced scattering coefficient μs′ ( is selecting aperture) and its slope is a quadratic function of γ. In the experiment, the diffuse reflectance of different μs′ was obtained with Intralipid, the linear relationship between diffuse reflectance and γ was verified. The γ of 2.04, the fractal dimension of 2.93 and the anisotropy factor of 0.816 were obtained by the slope, which were in good agreement with the parameters in literature, verifying the feasibility of the proposed method..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 9, 917002 (2018)
Dual Wavelength Fluorescence Microscopy Depth Imaging Based on Fresnel Lens Chromatic Aberration
HUANG Xin-rong, ZHENG Ji-hong, LIU You-rong, ZHU Tian-yun, and MIAO Tao
A technique about non-axial-scanning microscopic cell depth imaging is proposed. Fresnel lens are added into the microscopic system, and the chromatic aberration of a Fresnel lens is exploited to focus different excitation light wavelengths into different axial positions. It can realize the imaging of two or more focalA technique about non-axial-scanning microscopic cell depth imaging is proposed. Fresnel lens are added into the microscopic system, and the chromatic aberration of a Fresnel lens is exploited to focus different excitation light wavelengths into different axial positions. It can realize the imaging of two or more focal planes. Based on the excitation light wavelengths of 405 nm and 532 nm, two imaging detectors are added into the excitation path of a conventional fluorescence microscope to detect the imaging information of the image plane corresponding to two different focal planes. A fluorescence microscopic depth imaging system with a detection depth of about 12 μm is established. The imaging depth and axial resolution of the proposed system are compared with those of a fluorescence microscopic depth imaging system based on a microscope-less Fresnel lens. Experimental results show that the addition of Fresnel lens enables simultaneous imaging of different focal planes. For the same fluorescence band, the lateral resolution of the system is ensured while the imaging depth of field is expanded, the system can achieve multi-band simultaneous detection at different depths of fluorescent biological cells..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 9, 917003 (2018)
Transmission of Multipole Solitons in Parity-Time Symmetric Scarff Potentials
HU Su-mei, ZHONG Ting-ting, WU Hong-mei, ZHOU Qing-yun, and CHEN Hai-bo
The existence and stability of dipole and tripole solitons in Parity-Time(PT) symmetric Scarff complex potentials are investigated, including linear case, and self-focusing and self-defocusing nonlinear cases. For linear case, the PT-breaking points, eigenvalues and multipole linear modes for different modulated depthsThe existence and stability of dipole and tripole solitons in Parity-Time(PT) symmetric Scarff complex potentials are investigated, including linear case, and self-focusing and self-defocusing nonlinear cases. For linear case, the PT-breaking points, eigenvalues and multipole linear modes for different modulated depths of PT symmetry Scarff complex potential are obtained numerically. For nonlinear cases, the existence and stability of multipole solitons are studied in self-focusing and self-defocusing media. For a fixed modulated depth, the eigenvalue for multipole linear modes is equalt to the critical propagation constant bc of multipole solitons existence. Multipole solitons are stable with the propagation constants close to bc both for self-focusing and self-defocusing nonlinearities..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 9, 919001 (2018)
Numeric Analysis of Frequency-doubling of Ultrashort Pulses in Refractive-index-linear-modulating Crystals
ZHANG Liu-yang, YANG Ying, QU Yu-qiu, CHENG Guang-zhen, ZHAO Zi-jian, and PU Shao-zhi
Frequency-doubling in refractive-index-linear-modulating crystals was investigated numerically. In the case of depleted-pump, changes of conversion efficiency and pulse width with crystal length and band width of phase matching were studied. With the increase of pump pulses energy, pulses are broadened resulted from thFrequency-doubling in refractive-index-linear-modulating crystals was investigated numerically. In the case of depleted-pump, changes of conversion efficiency and pulse width with crystal length and band width of phase matching were studied. With the increase of pump pulses energy, pulses are broadened resulted from the unbalanced conversion of fundamental pulses at the different position of the crystal. Due to the modulation of refractive index, there are periodic oscillations in conversion efficiency and pulse width. Subsequently, by analyzing the chirp in harmonic waves, it was found that with the increase of crystal length, the normalized chirp coefficient increase first then decrease and finally tend to 1. The maximum of the normalized chirp coefficient is governed by modulated bandwidth and intrinsic bandwidth. Finally, the effects of phase mismatching parameter on conversion efficiency and pulse width was discussed and the results showed that phase mismatching parameter y determines the location of phasing matching of central frequency. When y=0 is considered, central frequency reaches phase matching at the middle of crystals where is beneficial to improve conversion efficiency and pulse quality..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 9, 919002 (2018)
Controlling Optical Solitions in Self-focusing Kerr Medium by Adding Potential Barrier (Trap)
LI Shu-qing, QIAO Shi-zhu, CHENG Yong-xi, YAN Yi-wei, and MA Hui-lian
In order to control solitons in Kerr medium, based on Schrodinger equation, the optical soliton transmission in nonlinear self-focusing Kerr medium, after adding Gaussian-type potetial barrier, Gaussian-type potetial trap, Scarf-Ⅱ barrier (trap) and periodic potential barrier (trap), was studied by fast Fourier transfoIn order to control solitons in Kerr medium, based on Schrodinger equation, the optical soliton transmission in nonlinear self-focusing Kerr medium, after adding Gaussian-type potetial barrier, Gaussian-type potetial trap, Scarf-Ⅱ barrier (trap) and periodic potential barrier (trap), was studied by fast Fourier transform numerical simulation. The soliton can be controlled by changing the height (depth) of potential barrier (trap), the width of the gaussian-type barrier (trap) and Scarf-Ⅱbarrier (trap), or the period of the periodic potential barrier (trap). There are different phenomena in optical soliton transmission, such as tunneling, cyclical swings, linear transmission, division and so on, by selecting the different parameters. The study is available for cotrolling the soliton and optical switch and photocontrol..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 9, 919003 (2018)
Design for Mid-range Diffraction Multifocal Intraocular Lens
LI Ji, and XUE Chang-xi
The Liou-Brennan (L-B) eye model is constructed using the optical design software ZEMAX. The material of Intraocular Lens (IOL) is hydrophobic acrylate. A multifocal intraocular lens with a diffractive surface on the anterior surface and an aspherical surface on the anterior surface is designed. The design uses 0th ordThe Liou-Brennan (L-B) eye model is constructed using the optical design software ZEMAX. The material of Intraocular Lens (IOL) is hydrophobic acrylate. A multifocal intraocular lens with a diffractive surface on the anterior surface and an aspherical surface on the anterior surface is designed. The design uses 0th order and +1 order of diffraction. When the object is in different positions, different diffraction orders play a role. For the designed IOL, the additional optical power is 1.66 D, the optical powers of the two focal points are correspond to 20 D and 21.66 D respectively. The establishment of small additional power aims to focus on optimizing the optical quality of the intraocular lens at the mid-distance. Firstly, the diffraction efficiency of the diffractive surface is calculated based on the theory of diffractive optics. The optical parameters of the diffractive surface and the aspherical surface is obtained by ZEMAX optical design software. Then the phase structure and the actual surface profile of the diffractive surface are simulated by MATLAB simulation software. Finally, The designed IOL is processed by a single point diamond lathe. According to the measured optical Modulation Transfer Function (MTF) The optical quality of the designed IOL is analyzed and the correctness of the additional optical power is verified by the measured defocus curve. The design meets the optical modulation transfer function (MTF) at 50 lp/mm greater than 0.3, which provides better visual clarity for cataract patients for different distances. The new type of intraocular lens uses in the working distance of 75.3 cm, providing theoretical and experimental basis for the application of small additional power intraocular lens..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 9, 922001 (2018)
Design of Stable Satellite-borne Doppler Asymmetric Spatial Heterodyne Interferometer Support Structure
BAI Yu-long, SUN Jian, HAO Xiong-bo, WU Jun-qiang, BAI Qing-lan, and FENG Yu-tao
In order to ensure the mechanical stability and thermal stability of the satellite-borne Doppler asymmetric spatial heterodyne interferometer on wind measurement, a low heat conduction and microstress support structure is designed, and the interferometer is clamped by the combination of bonding and elastic compression.In order to ensure the mechanical stability and thermal stability of the satellite-borne Doppler asymmetric spatial heterodyne interferometer on wind measurement, a low heat conduction and microstress support structure is designed, and the interferometer is clamped by the combination of bonding and elastic compression. Firstly, according to the structural characteristics and stability requirements of the interferometer, a ring bonding surface is proposed, the bonding surface is optimized and compared with the existing one. Then, in view of the question that the response stress of the interface between the interferometer and the base is too large under the condition of random vibration, a cover structure with pretension is designed to improve bonding reliability. Finally, finite element simulation and test are carried out to analyze and verify the low thermal conductivity and mechanical reliability of the interferometer assembly. Experimental results indicate that the ring bonding surface has a 63.54% reduction in the heat input from the base to the optical components under the same conditions than the existing one. The maximum response stress of the adhesive surface at random vibration is 2 MPa. The basic frequencies of the interferometer component are all above 1900 Hz. The relative error of the analysis and test results is less than 8.6%. The interferometer based on the ring bonding surface and pretension has the characteristics of low heat conduction and high mechanical reliability, the structure design is reasonable and the performance is reliable..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 9, 922002 (2018)
Design of Large Field of View Space Camera Optical System Based on Freeform Surfaces
LI Xu-yang, NI Dong-wei, YANG Ming-yang, and REN Zhi-guang
Freeform surface is applied to design a large field of view off-axis three-mirror optical system. The focal length of the system is 2 000 mm, the F-number is 12, and the field angle is 35°×1°. In the system, XY polynomial freeform surfaces are applied as the primary mirror and the tertiary mirror surfaceFreeform surface is applied to design a large field of view off-axis three-mirror optical system. The focal length of the system is 2 000 mm, the F-number is 12, and the field angle is 35°×1°. In the system, XY polynomial freeform surfaces are applied as the primary mirror and the tertiary mirror surfaces, and the primary mirror is designed as a convex surface, so that the meridional field of view reaches 35°, further widening the imaging field of view. Based on the optimized XY polynomial coefficients, Matlab software is used to simulate the XY freeform surfaces of the primary mirror and the tertiary mirrors. The design results show that the optical transfer function of the system in the full field of view is better than 0.4 at 63 lp/mm, the diameter of the diffusion spot is less than one pixel size, the maximum relative distortion is less than 3%, and the wavefront error value is better than λ/14. The system has high energy concentration and the imaging quality is close to the diffraction limit. It can be seen that the freeform surface has great advantages in improving the imaging field of view and imaging quality of the off-axis reflection optical system. The system overcomes the shortcoming of the small field of view in the radial direction of the conventional off-axis reflective optical system, and it is suitable for wide swath imaging..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 9, 922003 (2018)
Measurement of Dispersion Characteristics of Atomic Medium Utilizing Mach-Zehnder Interferometer
ZHAO Fa-gang, TIAN Zhuo-cheng, LIU Zhi-wei, YANG Bao-dong, and ZHOU Hai-tao
The measurement of the dispersion properties of the coherent medium by using homodyne method based on Mach-Zehnder interferometer is analyzed in theory, and then the dispersion properties of three-level Cs atoms medium in two completely opposite coherent effects, electromagnetically induced transparency and electromagnThe measurement of the dispersion properties of the coherent medium by using homodyne method based on Mach-Zehnder interferometer is analyzed in theory, and then the dispersion properties of three-level Cs atoms medium in two completely opposite coherent effects, electromagnetically induced transparency and electromagnetically induced absorption, are experimentally measured. The results show that at the atomic resonance center, the signal light can pass through the medium due to reduced absorption for the electromagnetically induced transparency medium, which ensure the measurement to the effective dispersion properties information, namely normal dispersion. On the contrary, for the electromagnetically induced absorption medium, due to the strong absorption effect, only at the low atomic densities, i.e. to ensure the signal light through the medium without being fully absorbed, the anomalous dispersion properties of the medium can be measured. Furthermore, when increasing the atomic number density, the absorption of atoms to signal light is enhanced to full absorption, and the absorption spectrum width is widened, which leads to the fact that phase shift can not be effectively measured..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 9, 927001 (2018)
Controlled Bidirectional Two-qubit Quantum Teleportation
WANG Si-meng, ZHANG Wei, and LIAO Cong
In order to achieve controlled bidirectional quantum teleportation of two qubits, based on tensor analysis, von Neumann and Bell basis measurements, we propose criteria for assessing whether an arbitrary nine-qubit entangled state can be used as quantum channel for controlled bidirectional quantum teleportation. Using In order to achieve controlled bidirectional quantum teleportation of two qubits, based on tensor analysis, von Neumann and Bell basis measurements, we propose criteria for assessing whether an arbitrary nine-qubit entangled state can be used as quantum channel for controlled bidirectional quantum teleportation. Using such a channel, the controller performs a von Neumann measurement, dividing the initial quantum channel into single, dual, triple and quadruple channel. In order to achieve CBQT of two qubits using the proposed criteria, taking the dual channel as an example, Alice, Bob, and the controller work together, using von Neumann measurement, Bell basis measurements, and finally unitary transformations. we verify the feasibility of the proposed standard and set out a general quantum channel selection method..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 9, 927002 (2018)
© Copyright 2018-2021 | Chinese Laser Press. All Rights Reserved 沪ICP备15018463号-20