Journals >Acta Photonica Sinica
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2012
Volume: 41 Issue 9
24 Article(s)
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Research Article
Theoretical Design of Thresholdtunable Optical Limiters Based on the Thermal Lens Effect of Magnetic Fluids
WANG Haotian, PU Shengli, and WANG Ning
The farfield beam patterns after the magnetic fluid sample are simulated. The scheme for realizing the thresholdtunable optical limiters is proposed. The relationship between the output power and the incident power at several different aperture radiuses and different distances between the aperture and the sample are The farfield beam patterns after the magnetic fluid sample are simulated. The scheme for realizing the thresholdtunable optical limiters is proposed. The relationship between the output power and the incident power at several different aperture radiuses and different distances between the aperture and the sample are investigated through theoretical calculations. The results show that the threshold value of the optical limiting system shifts to high power when the aperture radiuses are increased and the distances between the aperture and the sample are decreased. The linear relationship between the threshold value and the aperture radius is obtained. The threshold value of the optical limiting system decreases with the increase of the absolute value of the magnetic fluid characteristic parameter (f). The results presented in this work may be helpful for designing the magneticfluidbased thresholdtunable optical limiters..
Acta Photonica Sinica
- Publication Date: Aug. 31, 2012
- Vol. 41, Issue 9, 1009 (2012)
Principle of Dualbalanced Coherent Receive and Its Application in Heterodyne Interferometer
PANG Yajun, WANG Chunhui, and TANG Tiantian
The principle of optical dualbalanced coherent receive is deduced using Jones matrix, the IQ signal is obtained that contains all the optical information,and the signal processing algorithm based on the IQ signal to demodulate optical signal information is given. Based on this principle, a highspeed MEMS scanning lasThe principle of optical dualbalanced coherent receive is deduced using Jones matrix, the IQ signal is obtained that contains all the optical information,and the signal processing algorithm based on the IQ signal to demodulate optical signal information is given. Based on this principle, a highspeed MEMS scanning laser heterodyne interferometer is designed, and the thickness map of the test glass is obtained. The interferometer wavefront phase extraction accuracy achieves 0.01 radians, the measurement speed reaches 40 frame/s, and the maximum measured diameter can reach 300 mm, which show the broad application value in realtime optical detection..
Acta Photonica Sinica
- Publication Date: Aug. 31, 2012
- Vol. 41, Issue 9, 1015 (2012)
A Novel Ultraviolet Solid State Laser in Lithography
LEI Liang, LI Fan, LIN Qinghua, ZHOU Jinyun, and RAN Zuo
An intracavity frequencytripling of a diodeedgepumped passively Qswitched 1 064 nm Nd∶YAG laser is presented to generate high power 355 nm UV laser. Several essential technologies are put forward to achieve the best beam quality such as a volume grating to maintain quasi phase matching with narrow linewidth, optimiAn intracavity frequencytripling of a diodeedgepumped passively Qswitched 1 064 nm Nd∶YAG laser is presented to generate high power 355 nm UV laser. Several essential technologies are put forward to achieve the best beam quality such as a volume grating to maintain quasi phase matching with narrow linewidth, optimization and thermal effects compensation for cavity. The task first takes advantage of volume grating and two CBO crystals as SHG and THG nonlinear optical conversion material to obtain high UV laser power output more than 4 W, light quality factor M2<2.5, meanwhile it is the first time to realize thermal effect using 45° Faraday rotator. The achievement is expected to be the popular light source system in lithography instead of conventional excimer laser..
Acta Photonica Sinica
- Publication Date: Aug. 31, 2012
- Vol. 41, Issue 9, 1019 (2012)
Properties of Isochronal Chaos Synchronization of Semiconductor Lasers with Multiple Mutual Timedelayed Couplings
LIU Yingying, PAN Wei, JIANG Ning, and XIANG Shuiying
Based on systems of semiconductor lasers with two mutual timedelayed couplings and three mutual timedelayed couplings, the influence of coupling delays and coupling strength to isochronal chaos synchronization was numerically studied. A thought that one coupling delay could be seen as feedback delays was presented inBased on systems of semiconductor lasers with two mutual timedelayed couplings and three mutual timedelayed couplings, the influence of coupling delays and coupling strength to isochronal chaos synchronization was numerically studied. A thought that one coupling delay could be seen as feedback delays was presented in the system with two mutual timedelayed couplings. The condition and law for isochronal chaos synchronization was revealed in the system of semiconductor lasers with multiple mutual timedelayed couplings. The results show that the ratio 2 of two coupling delays is a basic condition to achieve isochronal chaos synchronization with high quality. Increasing coupling strength can improve the quality of isochronal chaos synchronization, and when the coupling strength is lower, the system with two mutual timedelayed couplings is much easier to achieve good isochronal chaos synchronization than system with three mutual timedelayed couplings..
Acta Photonica Sinica
- Publication Date: Aug. 31, 2012
- Vol. 41, Issue 9, 1023 (2012)
Nearinfrared Emission and Energy Transfer Mechanism of Tm3+/Yb3+ Codoped Tellurite Glasses
XU Xingchen, ZHOU Yaxun, WANG Sen, WEI Shulin... and WANG Xunsi|Show fewer author(s)
Tm3+ single doped and Tm3+/Yb3+ codoped tellurite glasses with the composition of TeO2ZnONa2O were prepared by meltquenching method. The intensity parameters Ωt(t=2, 4, 6), spontaneous radiative transition rates A, fluorescence branching ratios β and radiative lifetimes τrad of Tm3+ were calculated based on the JuddTm3+ single doped and Tm3+/Yb3+ codoped tellurite glasses with the composition of TeO2ZnONa2O were prepared by meltquenching method. The intensity parameters Ωt(t=2, 4, 6), spontaneous radiative transition rates A, fluorescence branching ratios β and radiative lifetimes τrad of Tm3+ were calculated based on the JuddOfelt theory, and the upconversion luminescence of Tm3+ for glass sample with different Yb3+ doping concentration was measured. The results show that the glass sample can emit strong nearinfrared upconversion emission under the excitation of 980nm pump light. The analysis of Tm3+ upconversion emission process reveals that the intense nearinfrared upconversion luminescence of Tm3+ ions is mainly ascribed to the result of energy transfers: first the resonant energy transfer from Yb3+ to Yb3+ ions, and then followed by one and two phononassisted nonresonant energy transfer from Yb3+ to Tm3+ ions. The energy transfer coefficient and phonon contribution for the above energy transfer process were calculated. Furthermore, the 1.8μm band absorption, emission crosssections and gain coefficient of Tm3+∶3F4→3H6 transitions were calculated and analyzed. The research indicates that Yb3+/Tm3+ codoped TeO2ZnONa2O glass is a promising host material applied for nearinfrared band solid laser..
Acta Photonica Sinica
- Publication Date: Aug. 31, 2012
- Vol. 41, Issue 9, 1028 (2012)
Characteristics of Pt/WO3 Hydrogen Sensitive Material Prepared by Solgel Method
YANG Zhi, YANG Minghong, DAI Jixiang, CAO Kun... and ZHANG Pengcheng|Show fewer author(s)
Nanostructured WO3 mixed with chloroplatinic acid was prepared by solgel method. Fiber Bragg grating was coated with the hybrid material. The asprepared powder was mixed with different ratio of chloroplatinic acid and annealed at different temperatures and their structures were characterized by Xray diffraction. TheNanostructured WO3 mixed with chloroplatinic acid was prepared by solgel method. Fiber Bragg grating was coated with the hybrid material. The asprepared powder was mixed with different ratio of chloroplatinic acid and annealed at different temperatures and their structures were characterized by Xray diffraction. The results show that the crystallinity of WO3 increases with the decrease of chloroplatinic acid and the increase of thermal treating temperature. The experiment demonstrates that after being annealed under 30℃ with the Pt∶W ratio of 1∶9, the sensor has good repeatability, can reach the response speed of 15 s to 4% Hz, and has 140 pm central wavelength change. The sensor shows no sensibility with further increase of temperature up to 500℃..
Acta Photonica Sinica
- Publication Date: Aug. 31, 2012
- Vol. 41, Issue 9, 1036 (2012)
Effect of Temperature and Vibration on Optical Fiber MachZehnder Interferometer and Dynamic Compensation
YU Xiangzhi, LI Zhengyong, WANG Zhihao, and WU Chongqing
Environment temperature changes and vibration will cause the random change of phase difference between two arms in the MachZehnder interferometer (MZI), resulting in the instability of interferometer outputs. In this paper, the effect of temperature and vibration on the 3×3 couplerbased interferometer was studieEnvironment temperature changes and vibration will cause the random change of phase difference between two arms in the MachZehnder interferometer (MZI), resulting in the instability of interferometer outputs. In this paper, the effect of temperature and vibration on the 3×3 couplerbased interferometer was studied in detail under natural conditions. Results show that the interference frequency caused by temperature and vibration is mainly concentrated in the low frequency section below 100 Hz. In order to eliminate these disturbances, a singlearm compensation feedback loop was designed to stabilize the output signal, and a dynamic compensation method was proposed based on quadrant judgment for distinguishment of positive and negative feedback. In the experiments, two of the three outputs of the 3×3 coupler are transformed from optical single to electrical one, and drives the piezoelectric ceramic to stretch the fiber wound on it after differential amplifier and other feedback circuits, which dynamicly compensate the phase difference drift of the interferometer and stablize the output namely the third output of the 3×3 coupler. Considering the disturbances caused by the temperature and vibration under nature environment, a stable dynamic compensation device was successfully demonstrated which can effectively suppress lowfrequency interference below 160 Hz, and compensate realtime the phase difference drift between two arms of the interferometer, while the output becomes stable with fluctuations less than 5.64%..
Acta Photonica Sinica
- Publication Date: Aug. 31, 2012
- Vol. 41, Issue 9, 1041 (2012)
Approach of Distance Improving of Atmospheric UV Communication
DING Ying, FAN Jingtao, TONG Shoufeng, JIANG Huilin, and DONG Keyan
The UV atmospheric transmission theory and the nonline of sight single scattering channel model were introduced. According to the model, the transmission loss caused by atmospheric channel under different structure design was quantitatively analyzed. Attenuation was quantitatively simulated under different atmospheresThe UV atmospheric transmission theory and the nonline of sight single scattering channel model were introduced. According to the model, the transmission loss caused by atmospheric channel under different structure design was quantitatively analyzed. Attenuation was quantitatively simulated under different atmospheres, communication patterns and structure parameters. Experimental results show that attenuation increases with increasing transmission distance; under different visibility, attenuation increasing different, and the higher visibility, the less attenuation, the far transmission distance; transmission distance increases with decreasing launching elevation and receiving elevation, and influence degree of launching elevation is more series than receiving elevation; transmission distance increases with increasing beam divergence angle and decreasing field angle, and influence degree of field angle is more series than beam divergence angle..
Acta Photonica Sinica
- Publication Date: Aug. 31, 2012
- Vol. 41, Issue 9, 1047 (2012)
Fiber Coupling System of Space Optical Field Based on Aspheric Lens
LI Shichun, HUA Dengxin, SONG Yuehui, and TIAN Xiaoyu
A telescope fiber coupling system using aspheric lens for coupling freespace optical field into singlemode fiber in allfiber lidar is devised. Its layout is designed and optimized for coupling efficiency into singlemode fiber through ZEMAX software. Moreover, the preliminary experiments are carried out using the LEA telescope fiber coupling system using aspheric lens for coupling freespace optical field into singlemode fiber in allfiber lidar is devised. Its layout is designed and optimized for coupling efficiency into singlemode fiber through ZEMAX software. Moreover, the preliminary experiments are carried out using the LED and laser as optical source, and then the coupling efficiencies of directive coupling and aspheric lens coupling are compared. Experimental results show that the coupling efficiency using aspheric lens for multimode optical source may be increased by 47% than that of directive coupling, which is close to simulating result of 45%, and that the ratio of coupling optical power for different fibers is roughly close to the square of the corediameter ratio. Furthermore, it is shown that the coupling efficiency of this way for singlemode optical source may be raised by 20%, and that the ratio of coupling optical power is approximately 2.4 times more than the square of its corediameter ratio, which is significant to establish the allfiber rotational Raman lidar..
Acta Photonica Sinica
- Publication Date: Aug. 31, 2012
- Vol. 41, Issue 9, 1053 (2012)
A Calibration Technique of Sensitivity of Fiber Grating Hydrophone
CHEN Yi, ZHANG Jun, JIN Xiaofeng, and HUANG Shengye
In order to calibrate the sensitivity of fiber grating hydrophone, a calibration technique of fiber grating hydrophone was studied. In this paper, the working principle of fiber grating hydrophone was introduced firstly. Secondly, using tunable laser and intensity modulation method with workpoint controlling, the signIn order to calibrate the sensitivity of fiber grating hydrophone, a calibration technique of fiber grating hydrophone was studied. In this paper, the working principle of fiber grating hydrophone was introduced firstly. Secondly, using tunable laser and intensity modulation method with workpoint controlling, the signal demodulation and stably measurement of fiber grating hydrophone was realized. Based on these methods, a calibration system of fiber grating hydrophone was established using comparison methods, and its calibration frequency range was 20 Hz to 10 kHz. Finally, using this calibration system, the sensitivity of a fiber grating hydrophone made of equivalent phase shift fiber Bragg grating was calibrated in the frequency range 20 Hz to 10 kHz, and measurement uncertainty of the system was estimated. The results proved that this system can correctly calibrate the sensitivity of fiber grating hydrophone, with its expand uncertainty (at k=2) of 0.9 dB..
Acta Photonica Sinica
- Publication Date: Aug. 31, 2012
- Vol. 41, Issue 9, 1059 (2012)
Improved Fast Blockmatching Algorithm for Sensor Electronic Image Stabilization
WANG Peng, ZHAO Yuejin, KONG Lingqin, DONG Liquan, and DAI Lu
An improved block density fast algorithm for steadying shaking image was presented. The jitter of camera system was measured by gyro, while the local motion vectors was estimated by the small area fast blockmatching algorithm, and the global motion vector was calculated by least square method. Small area fast blockmaAn improved block density fast algorithm for steadying shaking image was presented. The jitter of camera system was measured by gyro, while the local motion vectors was estimated by the small area fast blockmatching algorithm, and the global motion vector was calculated by least square method. Small area fast blockmatching algorithm, which has high calculating precision, is good at calculating the local motion vectors. So the least square method can exactly calculate global motion vector by using parts of the local motion vectors. For this reason, the black density can be improved to speed up the algorithm and retain the precision of the global motion vector at the same time. The small area fast blockmatching algorithm was optimized by analyzing the block gridding, and then the fast sensor electronic stabilization algorithm was designed. The simulation and experiment show that the algorithm is slightly more accurate and about 89% faster than the small area fast algorithm..
Acta Photonica Sinica
- Publication Date: Aug. 31, 2012
- Vol. 41, Issue 9, 1065 (2012)
Dynamic Performance of the PZT Driver Used in a Lithographic Objective
WANG Xueliang, and GONG Yan
The dynamic performance of a PZT driver which contains an operational amplifier was studied according to the specific requirements of the image quality compensator in a lithographic objective. Firstly, the impact of the inherent frequency characteristics of the operational amplifier on dynamic performance was analyzed The dynamic performance of a PZT driver which contains an operational amplifier was studied according to the specific requirements of the image quality compensator in a lithographic objective. Firstly, the impact of the inherent frequency characteristics of the operational amplifier on dynamic performance was analyzed and the parameters of the compensatory network were fixed. Secondly, the impact of the capacitive load of the driver system on dynamic performance was analyzed and the corresponding solution was provided. Finally, the impact of the parasitic capacitance in the driver system was discussed. As calculated, after compensated the PZT driver system had a phase margin of 79 degrees and a setting time of 5 microseconds, and presented no overshoot in step response. The driver would fulfill the dynamic requirements of strong stability, rapid response and little overshoot when the PZT was used as actuator of the image quality compensator in a lithographic objective..
Acta Photonica Sinica
- Publication Date: Aug. 31, 2012
- Vol. 41, Issue 9, 1071 (2012)
A Simulation Study on Optical Properties of Trap Pits Morphology of Multicrystalline Silicon
ZHANG Fayun
Optical properties of trap pit morphology of multicrystalline silicon (weaklyetched, normaletched and heavyetched) were simulated by solving the Maxwell and material equations, using RF MODULE of COMSOL Multiphysics version 3.5a. The varying laws of surface electric field a component, surface magnetic field y componentOptical properties of trap pit morphology of multicrystalline silicon (weaklyetched, normaletched and heavyetched) were simulated by solving the Maxwell and material equations, using RF MODULE of COMSOL Multiphysics version 3.5a. The varying laws of surface electric field a component, surface magnetic field y component and reflectivity of three kinds of trap pits were obtained. It is indicated that the value of surface electric field z component and surface magnetic field y component of weaklyetched trap pit is the least, and its reflectivity is the highest(about 35%)at wavelengh of 600nm; followed by that of normaletched trap pit, its reflectivity is about 17%; the value of surface electric field z component and surface magnetic field y component of heavyetched trap pit is the most, its reflectivity is the lowest(about 10%). Compared the experimental date with the simulation results, change trend of numerical simulation results are accorded with that of experimental ones, which provided for the practice production of acidic texturing of multicrystalline silicon as theory bases..
Acta Photonica Sinica
- Publication Date: Aug. 31, 2012
- Vol. 41, Issue 9, 1076 (2012)
LED Spectrum Modulation Technique Based on Optical Coating
HAO Honggang, WANG Wenliang, LUO Yuan, and RUAN Wei
According to the differences between the white LED spectrum and the visible light spectrum, the feasibility of using optical coating to improve the spectrum is discussed. Meanwhile, a novel method is proposed to eliminate blue band of the white LED spectrum. The transmittance of the required optical coating is calculatAccording to the differences between the white LED spectrum and the visible light spectrum, the feasibility of using optical coating to improve the spectrum is discussed. Meanwhile, a novel method is proposed to eliminate blue band of the white LED spectrum. The transmittance of the required optical coating is calculated, and the feasibility of method is analyzed. According to the spectrum of the single LED is different at the different temperatures, the transmittance of the required optical coating is calculated based on the spectrum of the single LED at the temperature 4.9°, 24°, 49°, and the feasibility of using optical coating to improve the temperature stability of the single LED spectrum is analyzed. The results show that the method of using optical film coated on the LED chip does not improve the structure of the white LED to make it similar with the visible light spectrum. The blue band of the white LED spectrum can be eliminated and improve the comfort of the spectrum using the designed optical thin film. The center wavelength and the relative luminous of the analyzed single LED can be stabilized at the 700 nm and 0.2 at the temperature 4.9°, 24°, 49° using the designed optical film. The similarity of the spectrum at the different temperature is improved greatly. The results contribute to the further application of LEDs..
Acta Photonica Sinica
- Publication Date: Aug. 31, 2012
- Vol. 41, Issue 9, 1081 (2012)
Influence of O2/Ar Ratio on the Properties of Transparent Conductive SnO2/Ag/SnO2 Trilayer Film
YU Shihui, DING Linghong, XUE Chuang, and ZHANG Weifeng
SnO2/Ag/SnO2 trilayer thin films were prepared on glass substrates by RF magnetron sputtering of SnO2 with different O2/Ar ratio and DC magnetron sputtering of Ag. Several analytical tools such as Hall measurements, fourpoint probe and ultravioletvisiblenear infrared (UVVisNIR) spectrophotometer were used to explSnO2/Ag/SnO2 trilayer thin films were prepared on glass substrates by RF magnetron sputtering of SnO2 with different O2/Ar ratio and DC magnetron sputtering of Ag. Several analytical tools such as Hall measurements, fourpoint probe and ultravioletvisiblenear infrared (UVVisNIR) spectrophotometer were used to explore the causes of the changes in electrical and optical properties. When O2/Ar ratio is 1∶14, the film had a figure of merit of 1.69×10－2 Ω－1, the resistivity is 9.8×10－5 Ω·cm, and the sheet resistance is 9.68Ω/sq, while the average transmittance is still as high as 85% in the visible light region. In addition, when O2/Ar ratio is 1: 14, The flexible SnO2/Ag/SnO2 trilayer thin films with excellent photoelectric performance can be obtained by magnetron sputtering on PET substrates, the average transmittance is above 85%, the resistivity is 1.22×10－4 Ω·cm, and the sheet resistance is 12.05 Ω/sq..
Acta Photonica Sinica
- Publication Date: Aug. 31, 2012
- Vol. 41, Issue 9, 1086 (2012)
Calibration of Characteristic Parameters for Xray Plane Crystal on the Automatic Xray Diffractometer
YANG Guohong, WEI Minxi, HOU Lifei, YI Tao... and LIU Shenye|Show fewer author(s)
Xray crystal characteristic parameters are the bases of identification of Xray crystal species and class, kinds of Xray crystal spectrometer fabrication, Xray lines intensity quantitative measurement and Xray monochromatic image diagnosis. On the automatic Xray diffractometer (XRD), based on stability and precisiXray crystal characteristic parameters are the bases of identification of Xray crystal species and class, kinds of Xray crystal spectrometer fabrication, Xray lines intensity quantitative measurement and Xray monochromatic image diagnosis. On the automatic Xray diffractometer (XRD), based on stability and precision control of θ and 2θ goniometer, special plane crystal holder was made. Bremsstrahlung and CuKα line were attenuated for 5 orders by 40 μmthick Nickel filter, Xray sources was to be CuKα monochromatic source, and transmission power of filter was the criterion of CuKα monochromatic source. For Xray Pentaerythritol(002) plane crystal of Crystal lattice (2d) and integral reflective coefficient (Rc) of CuKα energy were calibrated, there are 2d=(0.87 425±0.00 042)nm, Rc=(1.759±0.024)×10－4 Rad respectively. This kind of experimental method is efficient and convenient on XRD in common laboratory. On XRD, other monochromatic Xray sources can be obtained by changing the material of Xray tube, and integral reflective coefficient of different energy will be obtained by the same way..
Acta Photonica Sinica
- Publication Date: Aug. 31, 2012
- Vol. 41, Issue 9, 1090 (2012)
Phase Measuring Profilometry Based on Elliptic Pattern Grating
BIAN Xintian, JI Baowei, CHENG Ju, and ZUO Fen
A new method to measure the three dimensional (3D) shape is proposed. In the measurement, the elliptic fringe pattern was projected to the surface of the object and the 3D shape of the object can be reconstructed by this method based on phase measurement profilometry. Some calculation formulas for phase and height are A new method to measure the three dimensional (3D) shape is proposed. In the measurement, the elliptic fringe pattern was projected to the surface of the object and the 3D shape of the object can be reconstructed by this method based on phase measurement profilometry. Some calculation formulas for phase and height are derived. A result of our method is compared with that of the phase measurement profilometry (PMP), which shows that the measurement accuracy of this method can meet accuracy requirement of the measurement. Moreover, this method owns strong ability of antinoise. With large noise, this method also can reconstruct the 3D shape of object. Computer simulation and preliminary validate the feasibility of this method..
Acta Photonica Sinica
- Publication Date: Aug. 31, 2012
- Vol. 41, Issue 9, 1094 (2012)
Quantum Properties of the Binomial Field Interacting with a Cascade Threelevel Atom Beyond the Rotating Wave Approximation
CONG Honglu, TANG Duochang, LIU Xuehua, CHENG Shuang, and REN Xuezao
The squeezing effect and atomic population of the binomial field interacting with a cascade three level atom are calculated accurately without rotatingwave approximation(without RWA) by using the complete quantum theory. The influences of the binomial state field parameter η on the field squeezing effect and the maximThe squeezing effect and atomic population of the binomial field interacting with a cascade three level atom are calculated accurately without rotatingwave approximation(without RWA) by using the complete quantum theory. The influences of the binomial state field parameter η on the field squeezing effect and the maximum photon number M of the binomial state field on the atomic population are considered. The results obtained from using the numerical method show that with increase of the binomial state field parameter η, the duration of the squeezing effect increases at first and then decreases. The little indentation oscillation appears in the evolution curves of the field squeezing effect, which is caused by virtual photon without RWA. The period of the revivalcollapse increases with the increase of the maximum photon number M, and the atomic population can not collapse completely in the collapse regime, but displays little indentation oscillation. In addition the influence of the withoutRWA terms on the quantum properties of the system are discussed..
Acta Photonica Sinica
- Publication Date: Aug. 31, 2012
- Vol. 41, Issue 9, 1098 (2012)
Quantum Properties of the Field in the System of Atoms Interacting with Coupled Cavities Via a Twophoton Hopping Interaction
WU Daoyong
Two coupled cavities each containing one twolevel atom are considered, which interacts with cavity via a twophoton hopping. The evolution of the state vector of the system is given when the total excitation number equals two. The squeezing of field is investigated. By means of the numerical calculations, the influencTwo coupled cavities each containing one twolevel atom are considered, which interacts with cavity via a twophoton hopping. The evolution of the state vector of the system is given when the total excitation number equals two. The squeezing of field is investigated. By means of the numerical calculations, the influences of cavitycavity coupling constant and atomcavity coupling constant on the antibunching effect of field are discussed. The obtained results show that the field does not display squeezing, and the antibunching effect of field has a nonlinear relation with cavitycavity coupling constant or atomcavity coupling constant..
Acta Photonica Sinica
- Publication Date: Aug. 31, 2012
- Vol. 41, Issue 9, 1104 (2012)
Algorithm and Simulation Onboard Switching in Low Earth Orbit Quantum Satellite Communication
WANG Zhi, and NIE Min
Quantum satellite communication can meet the requirement of quantum mobile communication among sailing, aviation field with longdistance and extensiveness communications, and onboard switching is one of the key techniques in quantum satellite communication. Based on the onboard switching technique in low earth orbit (Quantum satellite communication can meet the requirement of quantum mobile communication among sailing, aviation field with longdistance and extensiveness communications, and onboard switching is one of the key techniques in quantum satellite communication. Based on the onboard switching technique in low earth orbit (LEO) quantum satellite communication, a novel algorithm is proposed that is terminal measuredistance method. By using this algorithm, the distances between terminals and its adjacent cell center are measured, and then the distances data are uploaded to the current satellite system, finnaly the satellite system compares the distances and determines whether to handover or not. Mathematical analysis and simulation results show that the proposed algorithm has high reliability, is easy to operate, and can smoothly switch between the different satellites..
Acta Photonica Sinica
- Publication Date: Aug. 31, 2012
- Vol. 41, Issue 9, 1108 (2012)
False Alarm Probability of Eavesdropping Checks for Controllable Quantum Secret Sharing
YE Tianyu, and JIANG Lizhen
The false alarm probability of eavesdropping checks on both AliceBob quantum channel and AliceCharlie quantum channel in the controllable quantum secret sharing protocol using GreenbergerHorneZeilinger states proposed by Y. Sun et al. is analyzed. The reason why the total false alarm probability of eavesdropping chThe false alarm probability of eavesdropping checks on both AliceBob quantum channel and AliceCharlie quantum channel in the controllable quantum secret sharing protocol using GreenbergerHorneZeilinger states proposed by Y. Sun et al. is analyzed. The reason why the total false alarm probability of eavesdropping checks in the controllable quantum secret sharing protocol using GreenbergerHorneZeilinger states is not equal to 0 lies in the randomness of measurement basis selection for eavesdropping checks. Afterward, an improved controllable quantum secret sharing protocol using GreenbergerHorneZeilinger states is proposed, based on using deterministic measurement basis for eavesdropping checks. Theoretical analysis shows that compared with the original one, the improved scheme can discover the eavesdropping from any internal dishonest participant with twice probability, and possesses much higher security. Moreover, the total false alarm probability of eavesdropping checks in the improved scheme is equal to 0..
Acta Photonica Sinica
- Publication Date: Aug. 31, 2012
- Vol. 41, Issue 9, 1113 (2012)
Remote Sensing Image Fusion Using Edge Information and Features of SAR Image Based on Curvelet Transform
LU Yaning, GUO Lei, and LI Huihui
Curvelet transform, as a method of multiscale geometric analysis, is more suitable for image processing than wavelet, and more appropriate for analyzing the image edge characteristics of curve and line, which has better approximation precision and sparsity description. In this paper, the methods of integrating SAR imagCurvelet transform, as a method of multiscale geometric analysis, is more suitable for image processing than wavelet, and more appropriate for analyzing the image edge characteristics of curve and line, which has better approximation precision and sparsity description. In this paper, the methods of integrating SAR image and MS image are proposed based on curvelet transform. SAR image and I image, which is given by a linear HSI transform are given by curvelet transform to obtain coarse coefficients and detail coefficients. The new coarse coefficients are obtained by using edge information and features of SAR image. The detail coefficients are dealt with traditional method that gets max of detail coefficients both I and SAR image.Then, the inverse curvelet transform gets the new intensity I image. Finally degree of distortion and space frequency are used to evaluate the result. The results of experiment indicate that the method excels those of based on HSI or curvelet transform in preserving spectral information and enhancing resolution..
Acta Photonica Sinica
- Publication Date: Aug. 31, 2012
- Vol. 41, Issue 9, 1118 (2012)
A New SAR Segmentation Algorithm Based on Nonconvex Regularization
SHANG Xiaoqing, YANG Lin, and ZHAO Zhilong
With multiplicative noise present, SAR image segmentation becomes difficult to implement.In this paper, a new energy functional model in introduced which is based on nonconvex regularization. This new model combines the regions as well as boundary properties, which can improve the accuracy of segmentation, and protect With multiplicative noise present, SAR image segmentation becomes difficult to implement.In this paper, a new energy functional model in introduced which is based on nonconvex regularization. This new model combines the regions as well as boundary properties, which can improve the accuracy of segmentation, and protect the geometric edges of the SAR images as far as possible. Segmentation of regions of interest is performed by numerical solution of the partial differential equations that are derived through minimizing the energy formulation. Experiments on both synthetic and real SAR images demonstrate the effectiveness of the proposed algorithm..
Acta Photonica Sinica
- Publication Date: Aug. 31, 2012
- Vol. 41, Issue 9, 1124 (2012)
Phase Unwrapping Algorithm Based on Graph Cuts
WANG Jinjiang, WU Mingyun, LIU Yang, CHANG Tianyu, and CHEN Yang
In electronic speckle pattern interferometry (ESPI), the true phase is generally extracted by the phasestepping method, which can only get the wrapped phase. Before the phase can be used to provide quantitative information, the wrapped phase must be unwrapped. But ESPI fringe patterns are contaminated with high levelsIn electronic speckle pattern interferometry (ESPI), the true phase is generally extracted by the phasestepping method, which can only get the wrapped phase. Before the phase can be used to provide quantitative information, the wrapped phase must be unwrapped. But ESPI fringe patterns are contaminated with high levels of speckle noise, the task of phase unwrapping remains a challenge. In this article, a novel phase unwrapping algorithm based on graphcuts is proposed, which treats the phase unwrapping problem as integer optimizations. By the method of energy minimization, the novel algorithm can accurately extract the phase from wrapped phase images containing large amount of noise without prefiltering. For the same simulated wrapped speckle phase map,the RMSE(root mean squared error) of the traditional MaskCuts and LeastSquare are respectively 11.707 6 and 4.977 5, while the new algorithm's RMSE is 0.9459.Numerical simulation and experimental results both verify the excellent antinoise performance of the new algorithm..
Acta Photonica Sinica
- Publication Date: Aug. 31, 2012
- Vol. 41, Issue 9, 1130 (2012)
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