Acta Photonica Sinica
Co-Editors-in-Chief
Yue Hao
NIE Min1, GAO Kun, YANG Guang, ZHANG Mei-ling, and PEI Chang-xing

In order to analyze the performance of free space quantum communication influenced by the atmospheric turbulence which is close to the ground , the relationship between the turbulence meteorological parameters and the entanglement of quantum channel was obtained according to the Tunick model of the atmospheric turbulence. For the quantum depolarization channel and amplitude damping channel, the equation between meteorological parameters and the channel capacity was established. The effect of turbulence on the quantum channel utilization was analyzed, and the performance simulation was carried out .The simulation results show that, when the atmospheric pressure is 100 kPa, the wind speed is 2 m/s, the temperature is 25℃ and relative humidity are 0.2 and 0.6 respectively, the degree of entanglement for the quantum channel are 0.27 and 0.18, the capacity of depolarizing channel are 0.951 6 and 0.946 5, the capacity of amplitude damping channel are 0.439 0 and 0.422 7, the utilization of quantum channel are 0.42 and 0.37, respectively. The various parameters of quantum communication channel and the meteorological parameters of the atmospheric turbulence close to the ground are closely linked. The reliability of quantum communication can be improved when the parameters of quantum communication system can be adjusted adaptively based on the meteorological parameters of the atmospheric turbulence closed to the ground.

Jan. 01, 1900
  • Vol. 45 Issue 7 70701001 (2016)
  • ZHOU Zhi-rong, HUA Deng-xin, YANG Rong, YAN Qing, CHEN Hao, and SONG Yue-hui

    According to the characteristics of Mie scattering lidar echo signal contaminated by noise in day background light, a de-noising method of wavelets was presented. The daylight direct current component was removed by wavelet transform, and the white noise from background light and electrical noise from detection system were reduced by wavelets soft threshold. To verify the feasibility of the de-noising method, Mie scattering atmospheric lidar echo signal was actually extracted and retrieved, the test results show that the effective detection range can be improved from 2.5 km to 5 km, and the contamination from electric noise and the background light noise can be reduced by the proposed method in measurement of experimentations.

    Jan. 01, 1900
  • Vol. 45 Issue 7 70701002 (2016)
  • HU Wei, ZHUANG Yi-qi, BAO Jun-lin, and ZHAO Qi-feng

    Electrical resistance and low-frequency noise of Mn-Co-Ni type infrared detectors were measured during space-simulated environment experiments. Two groups of samples were irradiated up to 150 krad(si) accumulated dosage with a cobalt-60 source at dose rate of 10 rad(si)/s and 0.1 rad(Si)/s), respectively. The results show that 1/f noise increased significantly at dose rate of 0.1rad(Si)/s, but almost unchanged at dose rate of 10 rad(Si)/s. Three thermal stresses, namely, short-term thermal burn-in without bias (40℃, hold for 4 h), extended thermal brun-in with DC bias (bias voltage of ±15 V, 40℃, hold for 600 h) and thermovacuum cycling (-40℃ to +40℃, 1℃/min, hold for 1 h, 20 cyclings), were successively applied to a third group of samples, the changes of electrical resistance of samples have similar behavior; however, the degradation of 1/f noise shows different trends, and all malfunctions present abrupt increment. Theoretical analysis shows that the degradations of 1/f noise during the short-term thermal burn-in and extended thermal burn-in with DC bias may be ascribed to the defects within the thermistor bulk, and the degradations of 1/f noise during thermal cycling may be ascribed to the defects at the contacts. These results suggest that noise figure is a sensitive parameters for describing the low-frequency noise degeneration of infrared detectors, and short-term thermal burn-in and thermal cycling are effective testing methods for discriminating 1/f noise of infrared detectors.

    Jan. 01, 1900
  • Vol. 45 Issue 7 70704001 (2016)
  • YAN Wei, REN Xin, LIU Jian-jun, and FENG Jian-qing

    Geometric positioning methods for earth remote sensing images cannot be used for Chang’E-3 (CE-3) moon-based Extreme Ultraviolet Camera (EUVC) images because of lack of control points. According to this present situation, working principle and related coordinate systems for EUVC were introduced, and a geometric positioning algorithm was proposed for EUVC observations based on telemetry parameters and strict coordinate transformation relationship. Algorithm of geometric positioning was researched and positioning accuracy was evaluated. The results show that the space pointing of EUVC optical axis and CE-3 lander’s position in Solar Magnetic System at image acquisition epochs can be calculated by the proposed algorithm for high-precision geocentric position. Geocentric position results can also be used to correct the original images to ensure the reliability of the EUVC observations and to realize CE-3’s scientific objective of the space environment detection.

    Jan. 01, 1900
  • Vol. 45 Issue 7 70704002 (2016)
  • WANG Wei-min, RUAN Dong-sheng, and JING Xu-feng

    By using the rigorous Fourier modal theory, the influence of the substrate refractive index, the incident angle, the normalized period and the normalized depth with different values on the diffraction efficiency of a sinusoidal grating microstructure was investigated. Also, the diffraction properties of the grating were analyzed. Based on the scalar diffraction theory and the effective medium theory, the diffraction efficiencies of the sinusoidal grating were calcualted at which the period is far greater than the incident wavelength and far smaller than the wavelength respectively. Using the different parameters of grating structure, comparing the results calculated by these two theories with that estimated by Fourier modal theory, the accuracy of the scalar diffraction theory and the effective medium theory was analyzed. The results show that when the refractive index of grating is about 1.5, the normalized depth is less than or equal to 1 and normalized period is greater than or equal to 5, the scalar diffraction theory can be used to calculate the diffraction efficiency of sinusoidal grating, the error is less than 3%; If the refractive index is increased to 3.42, only when the normalized period is greater than or equal to 10, the scalar diffraction theory can be used to estimate the diffraction efficiency and the error is less than 5%. Only zeroth transmittance light is propagating, effective medium theory is valid to evaluate the diffraction efficiency of sinusoidal grating. It is noted that the error of two simple methods is minimum at a normal incidence. Furthermore, the accuracy of scalar diffraction theory and effective medium theory decreases as the incident angle increasing.

    Jan. 01, 1900
  • Vol. 45 Issue 7 70705001 (2016)
  • CHU Zi-hang, ZHANG Yong-ai, HE Lin-chang, JIN Tao, ZHOU Xiong-tu, GUO Tai-liang, and YANG Lan

    A viewpoint controllable liquid crystal grating was presented, which was driven by two-layer staggered electrodes to control the deflection of liquid crystal molecules. AZO-SiO2-AZO driving electrodes with two-layer staggered structure were prepared on the glass substrate using lithography and vacuum coating technology. This grating avoids the blank area between the single-layer electrodes and expands the control area. Therefore the control area becomes complete and flexible. The optical images shows AZO electrodes and AZO electrodes with the width of 275.8are parallel interdigitated and isolated by SiO2 insulation layer on the glass substrate. Combining the drive circuit, the liquid crystal grating could control the ratio of the light shielding area and transmission area effectively. It has some application prospects in the field of three-dimensional display

    Jan. 01, 1900
  • Vol. 45 Issue 7 70705002 (2016)
  • SU Jian-jia, JIANG Pei-pei, CUI Wei, WU Bo, and SHEN Yong-hang

    To measure the temperature range from room temperature to 1 000℃, a sapphire-ruby fiber -based multi-probe thermometer was proposed. The thermometer system combines fluorescence lifetime with radiationand, which can measure the temperature of 8 probes at the same time. A digital iteration algorithm based on area balance was presented to measure the fluorescence lifetime. Compared with the Fast Fourier Transformation algorithm through simulation, the proposed algorithm features robust, high efficiency, strong anti-noise and immune to background level. The temperature test and stability test of the system were studied for a long time, the results show that the system has high stability and accuracy, the measured temperature range from room temperature to 1 000℃, the accuracy can be ±1℃.

    Jan. 01, 1900
  • Vol. 45 Issue 7 70706001 (2016)
  • TAO Chuan-yi, and WEI He-ming

    A passive structural health monitoring system was presented for sensing foreign-object impact by using a semiconductor optical amplifier-based Fiber Bragg Grating (FBG) sensor that monitors high frequency dynamic strains. Strains applied on the FBG sensors were encoded as wavelength shifts of the light reflected by the FBG sensor which were then converted into phase shifts and demodulated by the Michelson interferometer. A Proportion Integration Differentiation(PID) feedback controller was employed to prevent interference drifting away from quadrature due to temperature and low frequency fluctuations. The adaptability of the demodulator and the optimum optical path difference were investigated. The impact signal from FBG dynamic strain sensor is acquired at the frequency up to 197 kHz.

    Jan. 01, 1900
  • Vol. 45 Issue 7 70706002 (2016)
  • CUI Wei, SU Jian-jia, JIANG Pei-pei, WU Bo, and SHEN Yong-hang

    A compact and high-resolution multiplexed Fiber Bragg Grating (FBG) wavelength interrogation system was reported. A compact tunable Laser Diode(LD) covering wavelength from 1 546 nm to 1 558 nm is applied as the light source to improve the simplicity, wavelength resolution and the response rate of the FBG demodulation system. A standard HCN gas-cell is incorporated as the wavelength reference. The 1 pm quasi-continuous wavelength tuning of the LD over 12 nm is realized by the combination of current control on multiple electrodes. A spectral centroid algorithm is used to determine the FBG′s wavelentgth, which results in robustness of the demodulation and then the high accuracy of the FBG interrogation. The demodulation process is simulated. The experimental results show an excellent wavelength resolution of better than 1 pm and precision of about 2 pm, which corresponds to temeprature resolution of 0.1℃ around 1 550 nm in an FBG -based fiber sensor.

    Jan. 01, 1900
  • Vol. 45 Issue 7 70706003 (2016)
  • ZHU Xing-bang, SUN Quan-she, ZHENG Xiang-liang, HAN Zhong, and LIU Zhi-ming

    In order to overcome the defect of narrow frequency band and low accuracy exist in the traditional modulation phase shift method, a single mode fiber length measurement technique based on modulation phase shift method was proposed. The single mode fiber length measuring device was designed and developed using the high-speed modulation signal synchronization and high-frequency signal phase difference mearuring technology in the integrated vector network analyzer. An auto-control and data processing software based on VBA plug-in of vector network analyzer was complicated, then an automatic processing method of phase variation was illustrated. Single mode fibers with the length of 2 km, 40 km and 150 km weretested using the developeddevice at different wavelengths, the results show that the standard deviation of 2 km fiber length measuring value is better than 0.2 mm, and the standard deviation of 150 km fiber length measuring value is close to 0.01 m. The fiber distance can be precisionly measured by this device at 1 310 nm, 1 490 nm and 1 550 nm.The proposed device can be expected to provide a new technical approach for precisionly measuring of fiber length.

    Jan. 01, 1900
  • Vol. 45 Issue 7 70706004 (2016)
  • LI Jian-hui, ZHANG Yong-tang, and WANG Fang

    The single-mode fiber was heated tapering by flame brush method, forming an optical waveguide structure which has a core radius of micro-nanometer level, and the low-loss optical fiber tapered was optimized by the different coefficients of thermal insulation to meet insulation standards. The tapered optical fiber with the best shape was designed, whose constant cone angle is 2 mrad, wavelength is 400 μm and fiber radius is 4 μm. Matlab simulation results show that, the transmission perspective of tapered optical fiber with length of 23 mm is 99.7%, the radiation resistance of tapered optical fiber with length of 63mm is 99.6%. Since the power is coupled to the high-order mode, the loss is sufficiently suppressed, so that the optical coupling transmission of the tapered fiber with a constant taper angle can be achieved without sacrificing the quality of the transmission.

    Jan. 01, 1900
  • Vol. 45 Issue 7 70706005 (2016)
  • LI Hui-dong, FU Hai-wei, SHAO Min, YAN Xu, and JIA Zhen-an

    A kind of optical fiber refractive index sensor based on a fiber core etched air-bubble in-fiber Mach-Zehnder interferometer was proposed and demonstrated. A core etched standard single mode fiber was spliced to a thinner core single mode fiber to form an air bubble at the connecting point. By this method, a section of thinner core fiber was cascaded between two air bubbles to form a structure of (Air-Bubble)-Thin core fiber-(Air-Bubble) in-fiber Mach-Zehnder interferometer as a refractive index sensor. The air-bubble in the sensor serves as an optical coupler for modes conversion and the thin core fiber serves as sensing beams. The transmission spectrum of sensor was studied by experiment. The results show that, the dip power of the interference fringes changes with respect to surrounding refractive index with a good linearity,at the same time,the dip wavelength keeps low dependence on RI. The sensitivity of the sensor is -216.21dB/RIU in the range of 1.345~1.389. The sensor is a good potential candidate for bio-chemical measurements.

    Jan. 01, 1900
  • Vol. 45 Issue 7 70706006 (2016)
  • YANG Xiu-fang, WANG Ruo-jia, WANG Pei-pei, YANG Yu-xiang, SHAO Wei, and WANG Jian

    Theoretical model of the continuous wave radar life signal was improved by introducing the biological electric theory . Using the lifting wavelet transform and the improved threshold function denoising technique, the radar life signal of the strong noise was processed. The signal to noise ratio and the mean square error of the radar life signal of the 166.67 mm wavelength are optimized from 2.046 8 and 6.6969 to 1.763 9 and 0.9099, and 8.57 mm wavelength are optimized from 0.942 6 and 1.9806 to 2.541 8 and 1.286 0. The result indicates that the theoretical model of the continuous wave radar life signal is consistent with the actual situation and the denoising scheme can be applied to radar wave at different wavelengths.

    Jan. 01, 1900
  • Vol. 45 Issue 7 70707001 (2016)
  • LIANG Zhi-hu, ZHANG Xiao-ning, YUE Jun-feng, TU Zhen-tao, HUANG Tai-jun, LIANG Peng-fei, and WANG Li-min

    In order to improve the Mura defect of the liquid crystal display, a grayscale compensation was proposed. Based on the brightness distribution matrix of typical grayscales, bilinear interpolation and the most value filtering was used to filter image, and then calculate the target brightness of the full screen. According to the fitted curve of grayscales and brightness, the compensation data of grayscales was obtained. The results of the experiments which performed on a 55-inch liquid crystal display module show that Mura stripes of the images diplayed on the module disappeared, and the Mura indexes decreased by Mura compensation.It has little influence on the overall brightness and contrast of displayed image.

    Jan. 01, 1900
  • Vol. 45 Issue 7 70710001 (2016)
  • WU Di, FENG Hua-jun, XU Zhi-hai, LI Qi, and CHEN Yue-ting

    A method for window adjustment based on simplified focus model was proposed, which can be used in autofocus process of digital camera. Firstly, the field angles of initial focus window boundary points were calculated with initial positions of those points and initial image distance. After the lens moved, the field angles and new image distance were used to calculate the new positions of focus window boundary points. Thus the focus window was adjusted to follow the target. Experimental results show that the proposed method can estimate the drift caused by imaging magnification changing on condition that the object distance is unknown. Compared with stationary focus window, the proposed method can avoid interference of background information, thus making the evaluation function unimodal. Besides, the proposed method is independent of the defocus blur for its calculation process has nothing to do with the image content itself.

    Jan. 01, 1900
  • Vol. 45 Issue 7 70710002 (2016)
  • YU Tao, HU Bing-liang, GAO Xiao-hui, WEI Ru-yi, JING Juan-juan, and HOU Xiao-hua

    Combining the compensation corrections based on target dynamic tracking with the spectra extraction based on non-uniform fast Fourier transform, a method was proposed to realize the high precision correction of airborne remote sensing. Through the way of real-time attitude measuring, active correction, feedback compensation from position and orientation system under poor imaging condition of non-stable platform, the interferogram was obtained. The fused image and the spectral curves were obtained from the corrected interferogram by the spatial transformation and data extraction of non-uniformity. The results of airborne flight experiment show that the multi-spectral fusion image has a good quality, and the precision of spectrum recovery has been improved greatly compared with the traditional methods. The attitude measuing system based on the proposed method has a good environmental adaptability of airborne, which can be used not only for the poor stability platform but also for the other spectral imaging detection system besides the principle of interference spectroscopy imaging. The proposed method provides a way for the movement error correction of airborne integration hyperspectral image processing platform.

    Jan. 01, 1900
  • Vol. 45 Issue 7 70710003 (2016)
  • LU Bao-li, LIU Yu-liang, and WANG Xin-wei

    A compact touchless 3D fingerprint acquisition system was proposed in this paper. The system utilizes a single CCD camera as an image sensor and combines the CCD with a biprism to obtain stereo image pairs in one frame of the CCD. Then 3D fingerprint is established based on the stereo vision technique. The entire size of the compact encapsulated system is 12 mm×12 mm×10 mm. The experiment of a forefinger fingerprint acquisition was conducted based on this system and the measurement root mean square error is 0.022 mm. This work is expected to provide a miniaturized solution for 3D fingerprint acquisition with its easy operation and compact structure.

    Jan. 01, 1900
  • Vol. 45 Issue 7 70710004 (2016)
  • TIAN Ai-ling, MA Di, WANG Da-sen, LIU Jian, LIU Bing-cai, and ZHU Xue-liang

    Based on the wavelength tuning phase-shifting technology in Fizeau interferometer, a phase-shifting calibration method with step by step was presented. First, the n groups interferograms with t step were generatd , the step is π/2. Then, the error function for each step was built through the origin interferogram multiplied by n group of each step separately and making Fourier transform. Finally, the precision calibration was realized by calculating the extreme point of error function curve. The experiment results show that, the calibrating precision is better than the traditional ones and the calibration accuracy is up to 2 or 3 orders to compare with the traditional method. This new method not only avoids the random error, but also eliminates the accumulated error completely.

    Jan. 01, 1900
  • Vol. 45 Issue 7 70712001 (2016)
  • YUAN Kun, ZHANG Shu-qin, WU Yi-ping, and JIN Shang-zhong

    A improved double-beam structure in spectrophotometer was proposed which has an extra calibration light source in the design of the double-beam to calibrate both the main beam and the auxiliary beam in real time. The related optimisation spectral data sampling algorithm was presented to modify the change of sensor response efficiency caused by temperature change, the effect of the proposed structure with a series of customised experiments at at different ambient temperatures was evaluated. Experiment results show that when operated in an environment with a temperature change from 10℃ to 30℃, double-beam correction instrument is able to produce measurements repeatability, the standard deviation with an average is less than or equal to 0.03, and the maximum is less than or equal to 0.04, which is a significant improvement to existing products.

    Jan. 01, 1900
  • Vol. 45 Issue 7 70712002 (2016)
  • YAO Yu-cheng, LIU Dan-lin, HUANG Chu-yun, XU Guo-wang, and WANG Bei

    The theoretical model of the thermal effects of the Tm:YAG laser which works at a low temperature by heating the rod ends of crystal was established. The temperature, stress and optical distortion of the crystal were simulated by the finite difference method. The simulation results show that, the designing of heating the crystal rod ends can reduce the maximum stress of crystal and minimize the stress damage accordingly. Although the complexity of the distribution of the temperature and stress caused by the crystal rod ends heating can cause a complex refractive index distribution, but it makes little effect on the light propagation because of the small changing refractive index value. The heating area is small and has no enough influence on the laser packaging.

    Jan. 01, 1900
  • Vol. 45 Issue 7 70714001 (2016)
  • DAI Yuan, LI Jun, LI Wen-sheng, DONG Xuan, and LU Ji-dong

    Choosing the TP347H steel which is used for the boiler heating surface in the thermal power plants as a research object, the characteristic of plasma spectral of the samples with different surface states(the unground and the ground) was analyzed. The experiment results show that, the change trends of the acquired spectral data of the two surface states are great difference with the increase of the laser hitting times. For the unground samples, the characteristic spectral line of Ca can clearly be detected in the whole experiment process. For the ground samples, the characteristic spectral line of Ca only exists in the beginning. For the unground TP347H samples containing of the elements of Fe and Mn, the absolute spectral intensity increases rapidly then reduces with the increase of the laser hitting times. For the ground TP347H samples, the absolute spectral intensity increases rapidly firstly then keeps relatively stable within a certain range with the increase of the laser hitting times. The unground samples exists fouling and slagging on the surface, which can enhance the spectral intensity, plasma temperature and electron density in a certain extent. But the spectral data stability of ground partis is better than that of the ground samples.

    Jan. 01, 1900
  • Vol. 45 Issue 7 70714002 (2016)
  • ZHENG Li-gong, WANG Xiao-kun, XUE Dong-lin, LI Rui-gang, ZHANG Feng, ZHANG Zhong-yu, and ZHANG Xue-jun

    The testing method combining systemic wave aberration testing with subaperture stitching interferometry was proposed for measuring large off-axis convex aspheric mirror. The basic principle and process of the technology were analyzed and researched, and the stitching mathematical model was established. When the large convex surface is polished very well and the primary mirror and tertiary mirror of the optical system are fabricated by computer controlled optical surfacing and magneto rheological finishing, the three mirror astigmatism system can be aligned and adjusted. The wave aberration of each field can be tested by aligning and calibrating the optical system successively, and the phase map of the whole aperture can be calculated by the synthetical optimization stitching algorithm and interpolation. With engineering examples, a three mirror astigmatism optical system with a large convex aspheric mirror with the aperture of 292 mm×183 mm was fabricated and tested by the method. At last, the root mean square of the surface error is 0.017λ (λ=632.8 nm).

    Jan. 01, 1900
  • Vol. 45 Issue 7 70722001 (2016)
  • ZHANG Long, HU Wen-qi, ZHENG Lie-hua, and HAO Pei-ming

    By combining the advantages of Offner refractive compensator and Maksutov reflective compensator, aiming at the testing of concave aspheric surface with large aperture or large relative aperture, a novel null compensator named catadioptric compensator was proposed.This method uses double lens and single mirror to test concave aspheric surface, the compensator is set between the mirror under test and its curvature center. Based on third-order aberration theory, the calculating formulas of initial structure were derivated. By compensator design for a concave aspheric suface, the princple of the proposed method was verified. The aperture of the asperic surace is 1 000 mm, the vertex radius of curvature of the aspherical surface is 4 000 mm, the conicoid coefficien is 1.05, the inner hole diameter is 200 mm, the peak valley value of the residual wavefront error of the optimized system is 0.004 2λ. The result shows that the axial testing size of this compensator is short and the compensating ablility is strong. If central obscuration is allowed, it is available to test concave aspheric surface with large aperture or large relative aperture.

    Jan. 01, 1900
  • Vol. 45 Issue 7 70722002 (2016)
  • LI Zong-xuan, XING Li-na, and XIE Peng

    Crucial requirements were proposed on the Primary Mirror Assembly(PMA), such as high lightweighting, high stiffness, high stability and short manufacturing cycle. In order to satisfy those, a meniscus-like mirror lightweighting scheme based on ZERODUR was designed, and the flexural support structure bonded to the outer ring of the mirror shaft was optimized. Through a finite element analysis and design approach, the optimal dimensions of the flexural support were obtained. In order to verify the finite element analysis results, a modal test was performed on the PMA, and the required aspherical optical surface was polished and tested. Test results show that, the first natural frequency of PMA is 332.5 Hz, the relative deviation is only 2.5% to compare with the analysis result; the surface figure of PMA maintains a constain RMS of λ/40 while rotating at 0°, 120° and 240° around the horizontal optical axis respectively; the influence of zero-gravity state is achieved on surface figure of PMA. The PMA satisfies the design requirements.

    Jan. 01, 1900
  • Vol. 45 Issue 7 70722003 (2016)
  • MA Pei-pei, LIU Yang-yang, L Qun-bo, PEI Lin-lin, and FANG Yu

    From the output atlas theoretical model of the image replicating imaging system, to improve the existing 16-band system and focused on the design of large relative-aperture and compact system, the design and optimization of 16-band spectral imaging system were performed with Zemax-EE software. This work focused on the analysis of the problem of the image aliasing resulted from the birefringence of the prisms. By matching the spectral imaging system and using the Zemax muti-configuration, the imaging quality of the system was simulated. The viewing field angle is ±1.25°, the relative-aperture is 1∶3 and the size of the system is about 220 mm (z). The modulation transfer function of every viewing field of every wavelength is more than 0.75 under the Complementary Metal Oxide Semiconductors (CMOS) Nyquist frequency situation. Compared with the existing equivalent spatial resolution of 16-band image replicating imaging spectrometer, this design is more compact which meets the requirement of miniaturization. The diffraction limit and light quantity are improved, so the imaging quality is significantly improved. The research provides a new design basis for the theoretical study of new type of snapshot imaging technology and for the design of the image replicating imaging spectrometer.

    Jan. 01, 1900
  • Vol. 45 Issue 7 70722004 (2016)
  • XUE Yu, CHANG Jian-hua, and XU Xi

    The ro-vibrational spectra of the gas molecules is located in mid-infrared waveband, and then the information of the gas type and its concentration can be detected with a high precision based on the non-dispersive infrared technology. In this paper, a SF6 gas sensor was designed with the optical structure of the double light path of a single light, by utilizing a 2~20 μm electrically modulated thermal radiation source and a dual wavelength pyroelectric detector with the central wavelengths of 3.95 μm and 10.55 μm. The method of a radial basis function neural network algorithm was proposed to compensate the detection error caused by the variation of the ambient temperature. The experimental results show that the detection accuracy of this sensor is less than ±1.5%FS within the ambient temperature range of 10℃ to 35℃ and the gas concentrations from 0 to 0.200%. The relative standard deviation is 1.56%. It can effectively eliminate the nonlinear effects caused by the environmental temperature changing in measuring the gas concentration. Compared with the traditional compensation methods with the empirical formula or the temperature control scheme, our method has a better measuring accuracy and stability. Moreover, by using this method, the gas sensor doesn't need any temperature control module, which is beneficial to miniaturize the device size and reduce its cost.

    Jan. 01, 1900
  • Vol. 45 Issue 7 70723001 (2016)
  • WU Wen-ting, LIANG Zhong-cheng, ZHANG Le, ZHAO Rui, and KONG Mei-mei

    An optofluidic switch based on microfluidic bistable oscillator was designed, which is conducive to keep up with the trends of integration, miniaturization and low power consumption. The insertion loss of the two optical outputs are 1.03 dB and 0.18dB, respectively. Microfluidic bistable oscillator consists of two symmetrical cascaded normally closed micro-valves, the optical switch is made up of three embedded optical fiber waveguides in the oscillator output part. A micro-syringe pump is used to drive the liquid and finally control the states of the switch. The impact factors of switching cycles were studied by using simulation software. The results show that when the injecting flow rate changes from 0.2 mm/s to 1.0 mm/s, the switching cycle is reduced from 1.25 s to 0.26 s. Simultaneously, the duty cycle is approximately 0.5 owing to the symmetrical design. The threshold of valve is providing the linear relationship with the switching time constants. With the widening of the normally closed valve seat, switching cycle is increased; with the decrease of valve aspect ratio, switching cycle is reduced. Moreover, asymmetrical design of the valves can adjust the duty cycle of the micro-oscillator. By adjusting the threshold characteristic of the valve and changing the inlet flow rate, an optical switch with specific frequency as need can be designed.

    Jan. 01, 1900
  • Vol. 45 Issue 7 70723002 (2016)
  • CAO Yan-ting, CHEN Chao, LIANG Pei, and HUANG Jie

    For the multi-chips LED packaged by phosphor layers, the light propagation in blue chip and phosphor layer was simulated based on the mathod of Monte Carlo. The influence of the encapsulation efficiency on different distrances between chip and phosphor layer was analyzed. The result shows that, the encapsulation efficiency of conformal coating firstly rises, then drops with the increasing of the diameter. The flat remote coating has a higher efficiency compared with others. The maximum encapsulation efficiency reaches up to 77.183% for the flat remote coating while the gap of chips is set as 0.2 mm and the distance between chip and phosphor layer is 0.28 mm. The influence of the curvature radius of phosphor layer on encapsulation efficiency is small.

    Jan. 01, 1900
  • Vol. 45 Issue 7 70723003 (2016)
  • WANG Ya-li, LIN Zi-yuan, CHAI Yang, and WANG Sheng

    Monolayer molybdenum disulfide (MoS2) with large area and high quality have been grown using Chemical Vapor Deposition (CVD) method. The optical properties of MoS2 was characterized systematically and high performance n-type field-effect transistors were fabricated. The effect of applied electrical field on photoluminescence (PL) spectrum of monolayer MoS2 in the devices was also studied. The results showed that the strongest emission peak of the PL spectrum of monolayer MoS2 consist of two peaks, namely A- peak (Charged Exciton) and A peak (Intrinsic Exciton) at room temperature. The energy difference between the two peaks is about 35 meV. The main PL peak shows obvious redshift and intensity change via tuning the back-gate voltage from negative to positive. We also found that the intensity of these two peaks show opposite dependence on the back-gate voltage with spectrum analysis. These results were analyzed and we concluded that the carrier concentration of monolayer MoS2 can be effectively modulated by applied electrical field, which can further affect the intensity and shape of PL spectrum. These results provide significant basis for the research on the physical mechanism of the optical properties of two-dimensional material. Besides, the large-scale preparation of such devices also make it possible to apply these two dimension materials to optoelectronics devices and systems.

    Jan. 01, 1900
  • Vol. 45 Issue 7 70730001 (2016)
  • SHI Dong-po, YIN Xian-qing, ZHENG Yan-cheng, CHEN Wu, and FU Jia-xin

    In order to decrease the influence caused by the micellization and the interaction between Sodium Dodecyl Benzene Sulfonate (SDBS) and betaine on determination of SDBS or betaine in aqueous solution. Synchronous fluorescence spectra and spectrochemical method were utilized to analyze the concentrations of SDBS and betaine by adding 1∶1 (molar ratio) hydroxypropyl-β-cyclodextrin (HP-β-CD) according to the amount of SDBS in their complex aqueous solution.The results indicate that the Critical Micelle Concentration (CMC) values of SDBS could be greatly increased with increasing betaine concentration in SDBS and betaine complex aqueous solution. The CMC values of SDBS reduced from 1.256 mmol/L to 1.121, 0.989 and 0.684 mmol/L when the concentrations of betaine respectively increased from 0 to 1.0, 2.0 and 3.0 mmol/L in their complex aqueous solution. The synchronous fluorescence intensities of SDBS could also be easily affected by betaine even in low concentration SDBS solution (the concentration is lower than CMC). Meanwhile, effect of the interferences on the quantitative determination of betaine by spectrochemical method could be obviously increased in the presence of SDBS. Both the interferences of betaine on synchronous fluorescence spectrum of SDBS and the interferences of SDBS on the spectrochemical determination of betaine, could be greatly reduced by adding 1:1 HP-β-CD. The recovery rates of SDBS and betaine respectively changed from 104.2%~109.2% and 119.7%~159.6% to 101.5%~102.5% and 101.5%~103.0% in their binary complex aqueous solution.

    Jan. 01, 1900
  • Vol. 45 Issue 7 70730002 (2016)
  • WU Ying, SU Bo, FAN Ning, and ZHANG Cun-lin

    Based on the Terahertz metal grating resonant transmission phenomenon, a label free biosensor consisting of metallic grating, sample pool and high resistivity silicon substrate was designed by using the sensitive characteristic of surface plasmon resonance of metallic grating for the surrounding medium. Terahertz transmission spectrums of threonine and arginine solutions were measured by using this sensor with terahertz time-domain spectroscopy. The experimental results show that, the resonance frequencies of the threonine and arginine solutions change and shift between 0.6 THz and 0.75 THz with the increase of concentration, moreover, the spectra of the mixed samples of threonine and arginine is not linear superposition of the two spectra.

    Jan. 01, 1900
  • Vol. 45 Issue 7 70730003 (2016)
  • WU Bin-qing, YE Man-ping, SHI Ya-rong, ZHEN Xiao, ZHAO Chun-liu, and CHEN Hua-cai

    The effect of temperature on the fluorescence of milk powder was studied by fluorescence spectra and fluorescence lifetime technology. Firstly, the fluorescence of milk powder is mainly from casein determined by comparing the fluorescence spectra of milk powder, casein, lactose and vitamins. Secondly, as the temperature increases, the fluorescence intensity of infant formula powder, toddler formula powder, adult ordinary milk powder and casein are generally reduced. The trend of fluorescence intensity with temperature of toddler formula powder and adult ordinary milk is almost same. The change of the fluorescence intensity of infant formula powder with temperature is different, which shows a relatively slow-changing platform area. Casein′s fluorescence strength is a slow downward with increasing temperature, falling slower than milk. When heated to 90 degrees and then cooled to 25 degrees, casein was partially recovered, indicating that changes in the activity of the protein structural or fluorophore are partially reversible. Finally, the fluorescence lifetime of milk powder and casein at different temperatures were measured. Milk powder and casein have two lifetimes after double exponential fit, which can be derived from tryptophan and phenylalanine. As the temperature increases, fluorescence lifetimes of milk powder and casein are decreasing.

    Jan. 01, 1900
  • Vol. 45 Issue 7 70730004 (2016)
  • ZHUANG Qiu-hui, LIU Guo-jun, FU Xiu-hua, MA Zi, and WANG San-qiang

    By using the ion beam assisted deposition to evaporate the materials and utilizing the double film thickness monitoring method to control the thickness of each layer, a depolarised dichroic mirror with the incidence angle of 45°, the spectrum 808nm reflected and 1064nm transmitted was prepared, which was used in an all solid state 355 nm laser. The partial thin film samples were annealed at 250℃, then the transmittance was measured with a Lambda 950 spectrophotometer; the weak absorption value of coatings was measured by a surface thermal lensing technique before and after annealing; the laser-induced damage threshold was tested by a 1 064 nm Q-switch pulsed laser; the morphology of the samples was observed by NIKON microscope under the different laser energy. The experimental results show that, the transmittances of the films are T1064 is 99.6%, T808 is 0.04%, which meet the design requirements, and the optical performance of the film can meet the requirements of the all solid state 355nm ultraviolet laser system; the weak absorption value is decreased after annealing; Micro destruction of the film is emitted under the action of laser, which proves that the film will not evolve to a catastrophic failure.

    Jan. 01, 1900
  • Vol. 45 Issue 7 70731001 (2016)
  • ZHANG Jia-long, YAO Hong, DU Jun, JIANG Jiu-long, DONG Ya-ke, and QI Peng-shan

    A kind of locally resonant phononic crystal plate with composite unite was introduced, and the band gap characteristics and sound transmission loss of the proposed structure were investigated with the finite element methods. It is found that the interaction between the local resonances and the traveling wave modes in the plate results the locally resonant band gap, whose bandwidth and sound insulation effect depend on the interaction strength and the thickness of thin membrane by changing structure parameters. By changing the thickness of the thin membrane, the proposed phononic crystal structure is demonstrated to meet the normal flight. The results show that the structures possess sound insulation effect below 200 dB and highest sound transmission loss up to 150 dB. The study provides a theoretical basis to obtain good sound insulation effect, and has a potential application value in the reducing of noise and vibration in the aero-engine.

    Jan. 01, 1900
  • Vol. 45 Issue 7 70731002 (2016)
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