Journals >Acta Photonica Sinica
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2012
Volume: 41 Issue 6
24 Article(s)
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Research Article
Optical Design of Spaceborne Broadband Limb Sounder for Detecting Atmospheric Trace Gas
XUE Qingsheng
In order to meet the urgent requirements of detecting atmospheric trace gas in limb observation geometry, an optical system of spaceborne broadband limb sounder for detecting atmospheric trace gas is designed. The system is an imaging spectrometer with the working wavelength band from 0.3 μm to 0.7 μm, and its full fieIn order to meet the urgent requirements of detecting atmospheric trace gas in limb observation geometry, an optical system of spaceborne broadband limb sounder for detecting atmospheric trace gas is designed. The system is an imaging spectrometer with the working wavelength band from 0.3 μm to 0.7 μm, and its full field of view is 2.4°, focal length is 120 mm, and the relative aperture is 1∶6. To avoid the problems of the classical CzernyTruner spectrometer, such as low spatial resolution caused by large astigmatism, a modified CzernyTurner spectrometer is designed, in which astigmatism can be corrected simultaneously in a wide band. By matching the modified CzernyTurner spectrometer with a offaxis parabolic telescope，an example of limb sounder optical system is designed. Ray tracing, optimization and analysing are performed by ZEMAX software. The analyzed results demonstrate that the astigmatism is substantially corrected, and the MTF for different spectral band is more than 0.69, which satisfies the predesigned requirement and proves the feasibility of the astigmatismcorrection method..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 6, 631 (2012)
Design of CualFOV Athermal Optical System for Infrared Dualcolor
JIA Yongdan, FU Yuegang, LIU Zhiying, and WANG Zhijian
Dualcolor infrared optical systems can obtain LWIR and MWIR information simultaneously, which would be good for the target tracking and recognition. As to the needs of the infrared thermography, dual FOV /dual color infrared optical system is designed with simplified optical configuration. Dual color (4.4~5.4 μm/7.8~8Dualcolor infrared optical systems can obtain LWIR and MWIR information simultaneously, which would be good for the target tracking and recognition. As to the needs of the infrared thermography, dual FOV /dual color infrared optical system is designed with simplified optical configuration. Dual color (4.4~5.4 μm/7.8~8.8 μm) clear imaging is achieved, and double view switch (9°×6.75°/3°×2.25°) can be completed by switching variable group when F# is constant(2.68). Through rational distributions of IR material and focal power, the optical passive athermal design achieves. The results indicate that when the systems works on －40℃~60℃,the image plane is stable and the image quality is excellent, which can meet the using requirement of infrared thermographs..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 6, 638 (2012)
Selecting the Optimal Integral Grade for TDI CCD in Remote Sensing Cameras
L Hengyi, LIU Yang, and XUE Xucheng
In order to solve the problem that integral grade affects the imaging quality, a method of integral grade selection for remote sensing cameras is proposed. Firstly, a model of signal to noise ratio and integral grade is derived and another model of modulation transfer function, satellite attitude parameters, precision In order to solve the problem that integral grade affects the imaging quality, a method of integral grade selection for remote sensing cameras is proposed. Firstly, a model of signal to noise ratio and integral grade is derived and another model of modulation transfer function, satellite attitude parameters, precision of the TDICCD’s line transfer frequency and integral grade is as well formulated. Then, the viable integral grade range is obtained under the restrictions of the SNR and MTF targets based on the above two models. Consequently, the gain of the imaging system versus the optimal integral grade is given. Finally, experiments and comparisons are made to validate the proposed method. The results indicate that: the optimal integral grade can be selected based on our method, and the best imaging effect can be accordingly obtained; when the optimal integral grade is nonexistent, a comparative good integral grade can be also acquired; the imaging effects obtained under the proposed method is better than that of the conventional ones..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 6, 642 (2012)
Opticalpath Optimization Design of Compound Axis and APT Study of Airborne Laser Communication
L Chunlei, TONG Shoufeng, and SONG Yansong
A dualdetector compoundaxis APT scheme of airborne laser communication is proposed, according to the environment of communication link. The compound axis consists of Coarse Tracking Assembly (CTA) and Fine Tracking Assembly (FTA). A detailed analysis and optimization design of whole optical path structure is carried A dualdetector compoundaxis APT scheme of airborne laser communication is proposed, according to the environment of communication link. The compound axis consists of Coarse Tracking Assembly (CTA) and Fine Tracking Assembly (FTA). A detailed analysis and optimization design of whole optical path structure is carried out. Then a technique about switching between coarse beacon and fine beacon is put forward. This way improves energy density of fine beacon and therefore can make CCD high frame work. Finally, it improves servo bandwidth of FTA. CTA performances a wide range of pointing and tracking, with tracking accuracy of up to 120 μrad. However, servo bandwidth of FTA is greater than 300 Hz, with dynamic range of 5 mrad and tracking accuracy of 3 μrad. The planetoground laser communication demonstration experiment is successfully completed, with the distance of 17.5 km, the communication rate of 1.5 Gbps, and BER of less than 1E7..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 6, 649 (2012)
Offaxis Projection System Based on Three Reflectors with Zernike Polynomial Surfaces and Even Aspheric Surfaces
SUN Wenjun, ZHAO Liping, SUN Jingnan, LI Juan, LI Mengyang, and ZHI Hongwu
Three offaxis projection systems based on even aspheric surface reflectors and Zernike polynomial surface reflectors are designed using wave front aberrations analysis and modulation transfer function. The projection system consists of three reflectors, in which the number of Zernike polynomial surface reflectors is dThree offaxis projection systems based on even aspheric surface reflectors and Zernike polynomial surface reflectors are designed using wave front aberrations analysis and modulation transfer function. The projection system consists of three reflectors, in which the number of Zernike polynomial surface reflectors is different. The first mirror M1 is concave to reduce the size of the second mirror and obtain high contrast ratio. The second mirror M2 and the third mirror M3 are convex to achieve a shorter projection distance and little system aberration. Optical performance analysis show that the system based on three Zernike polynomial surface reflector is the best, the MTF is more than 60% at 60 lp/mm and system distortion is less than 2.0% under the condition of Fnumber=2.8, the magnification of 80. Compared results with references show that the designed system based on three Zernike polynomial surface reflectors can more easily eliminate system aberrations, shorten system thickness and increase the visual angle and relative aperture..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 6, 654 (2012)
Preconditioning Experiment Research of Microchannel Plate Photon Counting Imaging Detector
NI Qiliang, BU Shaofang, LIU Shijie, HE Lingping, and ZHANG Hongji
A preconditioning process encompassed vacuum baking and burnin with ultraviolet radiation. An equipment of preconditioning of microchannel plate was designed which could provide vacuum environment (10－5 Pa at least) as well as heating elements. The heating elements were controlled to reach 350℃ and then the vacuum chaA preconditioning process encompassed vacuum baking and burnin with ultraviolet radiation. An equipment of preconditioning of microchannel plate was designed which could provide vacuum environment (10－5 Pa at least) as well as heating elements. The heating elements were controlled to reach 350℃ and then the vacuum chamber was sustained 350℃ for 18 hours in the procedure of bakeout. The burnin procedure illuminating with ultraviolet radiation (253.7 nm) from a deuterium lamp was achieved when 0.06 Coulomb cm－2 was extracted from the MCP stack output. After the preconditioning the image spatial resolution reached to 125 μm, the background events rate dropped to be 0.53 counts/s·cm2 from 27.09 counts/s·cm2, the pluse height distribution curve closed to Gauss distribution and turned to be more narrow..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 6, 658 (2012)
Photosensitive Polymers Used in LEDs Planar Phosphor Coating
DING Kun, RAO Haibo, and SONG Jirong
Adopting the photosensitive polymers + phosphor for LED conformal coating to realize the white LED phosphor coating planarization process, this technology enables the device to give off bright light and more self color space than the traditional packaging process, and spot color between single tube and the deviation ofAdopting the photosensitive polymers + phosphor for LED conformal coating to realize the white LED phosphor coating planarization process, this technology enables the device to give off bright light and more self color space than the traditional packaging process, and spot color between single tube and the deviation of brightness is less than 6%. Integrating photosensitive of PVA and physical chemistry performance of silicone and adopting emulsion technology in slip method process, the phosphor surface coating of PVA and silicone is realized, which is help to improve phosphor layer′s physicochemical properties. The improvement of effective refractive index of multiple phase coating is more helpful to improve the whole luminous efficiency of device. Because the range of photopolymer′s sensitive wavelength is very wide, besides the technology of adding to photosensitive, so that its photosensitive wavelength range is match to LEDs emitting wavelength, so white LED conversed by variety of phosphor can achieve planar coating technique. Because the majority of photopolymers are easy to absorb UV light, the traditional casting technology of UV+ threecolor phosphor will be greatly improved..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 6, 664 (2012)
Characteristics of Magnetic Sensitivity of Zerolock Laser Gyro
CAO Yaohui, HAN Zonghu, CHEN Linfeng, and FU Xin
Compared to the dithered ring laser gyro with the linearly polarized light running in the cavity, the Zerolock Laser Gyro(ZLG) with the circularly polarized light running in the cavity is more sensitive to the magnetic field. In order to reduce the magnetic sensitivity of the ZLG, the magnetic sensitivity of the ZLG iCompared to the dithered ring laser gyro with the linearly polarized light running in the cavity, the Zerolock Laser Gyro(ZLG) with the circularly polarized light running in the cavity is more sensitive to the magnetic field. In order to reduce the magnetic sensitivity of the ZLG, the magnetic sensitivity of the ZLG is theoretically analyzed. When the relative sacle factor corrections of left and right circularly polarized gyros are equal, the bias of the ZLG will not vary with the magnetic field. Further more, the linearity of relative scale factor correction will be improved. The magnetic sensitivity of the ZLG is experimentally tested, and the results indicate that the insensitivity point with respect to the magnetic field is existent, which is consistant with the theroretical analysis. Compared to the method of traditional passive magnetic shielding, the method of operating ZLG on the insensitive point by active control is proved to be of great practical value for reducing the magnetic sensitivity and improving the accuracy of the ZLG..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 6, 668 (2012)
A Hyperspectral Remote Sensing Image Endmember Extraction Algorithm Based on Modified Extendedmorphological Operator
WANG Ying, LIANG Nan, and GUO Lei
Applying the morphological operator, which characterizes the spatial correlative informations of pixels, to endmember extraction of hyperspectral remote sensing image can improve the performance of algorithm effectively. In order to overcome the limitations in sorting rules and replacing criteria of extendedmorphologiApplying the morphological operator, which characterizes the spatial correlative informations of pixels, to endmember extraction of hyperspectral remote sensing image can improve the performance of algorithm effectively. In order to overcome the limitations in sorting rules and replacing criteria of extendedmorphological operator, which is commonly used in hyperspectral remote sensing image to extract endmembers, the modified extendedmorphological operator is proposed after introducing the concept and presenting the calculating method of reference vector. The crossreplacement phenomena at the junction of different classes can be avoided and the correct coverage direction can be ensured when the modified sorting rules and replacing criteria have been applied in endmember extraction algorithm to enhance the results as key means. The endmember extraction algorithm using the determine profiles, generated after openclose and closeopen operations defined by basic dilation and erosion operations of modified extended morphology, is described in detail. The automated modified extendedmorphological endmember extraction algorithm is achieved by using both spatial and spectral information in a combined manner, thus, the endmember extraction result is superior to the approachs designed from a spectral information viewpoint only. The alogrithm is implemented in IDL7.0 and testd by using real hyperspectral imagery collected by airborne visible/infrared imaging spectrometer in cuprite area, the experimental results of the similarity on spectral curves, the average similarity and the mineral distribution maps verified the validity of the algorithm..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 6, 672 (2012)
Research on the High Resolution Trace Gas Detection Based on the Differencefrequency Midinfrared Spectrometer
CHEN Dong, ZHANG Bokun, HU Xie, LIU Wenqing, and ZHANG Yujun
Midinfrared spectral region is favorable for high sensitivity trace gas detection. The development and characterization of a compact midinfrared laser spectrometer for high resolution spectroscopic detection of trace gases is reported. Continuouswave midinfrared radiation is generated by differencefrequency mixingMidinfrared spectral region is favorable for high sensitivity trace gas detection. The development and characterization of a compact midinfrared laser spectrometer for high resolution spectroscopic detection of trace gases is reported. Continuouswave midinfrared radiation is generated by differencefrequency mixing of outputs of two commercial narrow linewidth diode lasers. A maximum midinfrared radiation power of 1 μW at 3.31 μm is generated, and the wavelength tuning region is around 3.2 μm to 3.7 μm. The highresolution spectroscopy capability of this spectrometer is evaluated by trace CH4 measurement, the line at 3 028.751 cm－1 of v3 fundamental vibrational band of CH4 is chosen as target analysis line for this line is relatively free of interference by other gas species. The detection sensitivity for CH4 is estimated to be 0.8 ppm for 10 cm optical path length at atmospheric pressure, and the limitation is supposed mainly from the etalon noise of optical surfaces..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 6, 678 (2012)
Influence of Hemoglobin on Noninvasive Optical Bilirubin Sensing
JIANG Jingying, GONG Qiliang, and XU Kexin
The spectral data were analyzed by using the Partial Least Squares Regression. The result shows that the addition of hemoglobin changes the number of principle component from one into three, while the largest contribution wavelength changes from 459 nm to 432 nm and 433 nm. This indicates that absorption noise of hemogThe spectral data were analyzed by using the Partial Least Squares Regression. The result shows that the addition of hemoglobin changes the number of principle component from one into three, while the largest contribution wavelength changes from 459 nm to 432 nm and 433 nm. This indicates that absorption noise of hemoglobin was introduced in the spectral data used for PLS model. Furthermore, compared with pure bilirubin solution, the Root Mean Squared Error of Prediction(RMSEP) of the model for mixed solution increases 24.90%, and the correlation coefficient of the model for mixed solution reduces 0.29%. It means that the addition of hemoglobin decreases the prediction ability of the model. Meantime, a new absorption peak at 408 nm appears, which seems there is a hypochromic effect, due to some weak key combinations between hemoglobin and bilirubin. And the new absorption peak changes the number of principal components and reduces the predictive ability of the model. Overall, the influence of hemoglobin should be reduced in order to improve the transcutaneous detection accuracy of bilirubin..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 6, 684 (2012)
Spectral Properties of Thylakoid Solutions of Spinach and Suzhou Green
LU Liping, HAN Caiqin, WEI Liangshu, LUO Xiaosen, and NI Xiaowu
The mechanism of the static low magnetic field action on thylakoid solutions was studied by analyzing the Raman spectra and PSII fluorescence of the spinach and Suzhou Green both excited by the light with different wavelength and to the changes in the spectra of the two samples treated by different magnetic fields withThe mechanism of the static low magnetic field action on thylakoid solutions was studied by analyzing the Raman spectra and PSII fluorescence of the spinach and Suzhou Green both excited by the light with different wavelength and to the changes in the spectra of the two samples treated by different magnetic fields with the same excitation wavelength. The results indicated that there were a lager number of Hydrogen bonds in the thylakoid solution. The Raman spectra were 531 nm and 532.2 nm and the PSII fluorescence were 689.8 and 686 nm for the spinach and Suzhou Green solution before the treatment by magnetic field. But the Raman spectra changed to 533.2 nm and 532.8 nm, and the PSII fluorescence were 686.8 nm and 685.4 nm for the two sample after the treatment. The static low magnetic field can change the Hydrogen bond energy to a constant value in the two solutions..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 6, 689 (2012)
Structural and Optical Properties of Zn3N2 Films Prepared by Magnetron Sputtering in NH3Ar Mixture Gases
LI Hongguang
The Zn3N2 is a kind of wide band gap semiconductor and it can be converted into ptype ZnO:N after oxidation at temperatures higher than 400°C which has significant potential for electronic and optoelectronic applications. The Zn3N2 films were prepared by RF magnetron sputtering a metallic zinc target in NH3Ar miThe Zn3N2 is a kind of wide band gap semiconductor and it can be converted into ptype ZnO:N after oxidation at temperatures higher than 400°C which has significant potential for electronic and optoelectronic applications. The Zn3N2 films were prepared by RF magnetron sputtering a metallic zinc target in NH3Ar mixture gases on glass substrate at room temperature. The optical transmission, optical absorption, structural property, chemical bonding states, photoluminescence were measured using a double beam spectrophotometer, Xray diffractometer (XRD), Xray Photoelectron Spectroscopy (XPS), fluorescence spectrometer. The effects of NH3 ratio on the structural and optical properties of the films were examined. XRD analysis indicates that the films are polycrystalline and have a preferred orientation of (321). The intensity of the Zn3N2 (321) peak increases with the NH3 ratio. The films prepared with the NH3 ratios of 5%~10% have low transmission values, the transparency of the films get better with the increase of the NH3 ratio. The Zn3N2 films have an indirect band gap, the optical band gap increases from 2.33 to 2.70 eV when the NH3 ratio varies from 5% to 25%. XPS analysis shows that the Zn3N2 film is easily hydrolyzed by air moisture. Photoluminescence spectrum shows two emission peaks, which are located at 437 nm and 459 nm..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 6, 695 (2012)
Fabrication of CuO Films and the Study of Its Photovoltaic Properties
ZHANG Junshan, GUO Linxiao, GAO Fei, LIU Xiaojing, SONG Meizhou, and LI Ning
pCuO films were deposited on nSi and glass substrates through reactive magnetron sputtering. The structural and optical properties of the pCuO films were investigated using Xray diffraction (XRD) and UVVisNIR spectrophotometer. The average crystal size and optical band gap of the deposited pCuO films were determpCuO films were deposited on nSi and glass substrates through reactive magnetron sputtering. The structural and optical properties of the pCuO films were investigated using Xray diffraction (XRD) and UVVisNIR spectrophotometer. The average crystal size and optical band gap of the deposited pCuO films were determined to be ~8 nm and ~1.36 eV, respectively. The formation of a pn junction between the pCuO film and nSi substrate was confirmed by examining the currentvoltage behavior of the junction. The pCuO/nSi junction cell had an opencircuit voltage of 0.33 V and shortcircuit current density of 6.27 mA/cm2 under AM 1.5 illumination. The fill factor and energy conversion efficiency were 0.2 and 0.41%, respectively..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 6, 700 (2012)
Optical Properties of Cudoped Ga2O3 Thin Films
YAN Jinliang, and ZHAO Yinnü
Polycrystalline Ga2O3 and Cudoped Ga2O3 thin films are prepared by RF magnetron sputtering and N2 ambient annealing. The Xray diffractometer, UVVIS spectrophotometer, fluorescent spectrometer are used to characterize and analyze the structural and optical properties. The experimental results show that the crystal quPolycrystalline Ga2O3 and Cudoped Ga2O3 thin films are prepared by RF magnetron sputtering and N2 ambient annealing. The Xray diffractometer, UVVIS spectrophotometer, fluorescent spectrometer are used to characterize and analyze the structural and optical properties. The experimental results show that the crystal quality deteriorates, the transmittance decreases, the absorption increases, and the effective optical band gap shrinks for Ga2O3 films with Cu impurity doping. The UV, blue and green characteristic emission bands of intrinsic Ga2O3 films are observed. The UV and blue emission are enhanced by Cudoping and a new emission peak centred at 475 nm appears for the Cudoped Ga2O3 films..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 6, 704 (2012)
KGW External Resonator High Power 579 nm Raman Yellow Laser
JIN Chenjie, LI Lifei, REN Zhaoyu, BAI Jintao, BAI Yang, and HE Qingli
The output characteristics of 579 nm high power resonator KGd(WO4)2 Raman yellow laser were reported. 579.54 nm yellow laser was generated based on 808nm pulse LD sidepumped ceramic Nd∶YAG, BBO electrooptical Qswitched and typeI critical phasematching LBO crystal extracavity frequency doubling project. With the 5.The output characteristics of 579 nm high power resonator KGd(WO4)2 Raman yellow laser were reported. 579.54 nm yellow laser was generated based on 808nm pulse LD sidepumped ceramic Nd∶YAG, BBO electrooptical Qswitched and typeI critical phasematching LBO crystal extracavity frequency doubling project. With the 5.02 W, 10.1 ns and 1 kHz output power pumped at 532 nm, the laser produced high average power of 2.58 W and pulses of 7.4 ns duration secondStokes wavelength at 579.54 nm. Conversion efficiency was 51.4% and slope efficiency was 54.8%. The beam quality factors M2 of 579.54 nm were M2x－579.54=5.829, M2y－579.54=6.336 and power instability less than ±2.35%. Experimental results indicate that external resonator Raman structure is an effective method for obtaining Raman yellow laser with its high opticaltooptical conversion and good power stability. Moreover, the additional usage of pulse LD with synchronous electrooptical Qswitch could generate high repetition rate, high average power, narrow pulse width and high peak power yellow laser..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 6, 708 (2012)
Thermal and Dynamics Damage in Combustion Chamber Case under High Power Laser
LUO Jijun, XU Jun, HOU Suxia, ZENG Zhenwu, ZHAO Yunfang, and YUAN Bo
According to internal pressure effect and without internal pressure effect, the temperature field, thermal stress, strain and the damage of the combustion chamber case under the laser irradiation, are calculated and analyzed respectively, based on the finite element analysis software ANSYS. Analysis results show that, According to internal pressure effect and without internal pressure effect, the temperature field, thermal stress, strain and the damage of the combustion chamber case under the laser irradiation, are calculated and analyzed respectively, based on the finite element analysis software ANSYS. Analysis results show that, the distribution of the shell temperature field and beam power is identical, and the maximum temperature is at the center of spot. The maximum stress is not in the center, but is located in the flare edg. If the shell absorption of laser power density is lager than 1 000 W/cm2 , the stress of the shell will be greater than limited stress and the shell will soften. In the presence of internal gas pressure condition, shell stress produces a local focus, along the circumferential surface by laser spot center axis region crack probably. Compared with no internal pressure shell, the stress and deformation produced by the shell with internal pressure are greater. In order to achieve the same damaging effects, in the circumstances of exist internal pressure, the laser radiation intensity can be appropriately reduced..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 6, 713 (2012)
Investigation of GeGeSe2In2Se3AgI Chalcogenide Glasses
WANG Yonghui, CHEN Fen, WANG Guoxiang, SHEN Xiang, ZHOU Yaxun, LI Jun, and DAI Shixun
(100－x)(4GeSe2In2Se3)－xAgI (x=20,30,40 mol%) chalcogenide glasses were prepared by traditional meltquenching method. In this paper, the Xray diffraction(XRD),differential thermal analysis (DTA), visible/nearinfrared absorption spectroscopy, infrared transmission spectra,Raman analysis were adopt to the analysis of (100－x)(4GeSe2In2Se3)－xAgI (x=20,30,40 mol%) chalcogenide glasses were prepared by traditional meltquenching method. In this paper, the Xray diffraction(XRD),differential thermal analysis (DTA), visible/nearinfrared absorption spectroscopy, infrared transmission spectra,Raman analysis were adopt to the analysis of the relationships of the composition, structure, thermal stability, and optical properties of the GeSe2In2Se3AgI ternary glass system. The Tauc equation was used to calculate the indirect optical band gap. From the heatingrate dependence of crystallization temperature, the activation energy for crystallization(E) was calculated by the Kissinger equation.The glass samples are amorphous, resulting in a wide composition range of glass formation. A maximum ΔT value of 114℃ and the activation energy for crystallization(Ea=320.4 kJ/mol) were obtained for the glass composition 70(4GeSe2In2Se3) 30AgI. With the addition of AgI, the shortwave absorption of the glasses shifts to the shorter wavelength and the optical band gap increases. In addition, the infrared transmission spectra shows that these prepared glasses all have wide optical transmission and there has been no significant change in infrared cutoff wavelength of the glasses which are all 16 μm or so..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 6, 718 (2012)
Preparation and Optical Properties of Polysiloxane Microspheres/PMMA Light Scattering Materials
TANG Huaqing, TANG Zhenfang, ZHAO Tingting, LI Wanli, and YE Qin
Light scattering materials with polysiloxane microspheres as the light scattering agents and poly(methyl methacrylate) as the matrix were prepared by mixed method. The influence of concentration and the particle diameter of light scattering agents on the total transmittance and diffusivity were studied and compared witLight scattering materials with polysiloxane microspheres as the light scattering agents and poly(methyl methacrylate) as the matrix were prepared by mixed method. The influence of concentration and the particle diameter of light scattering agents on the total transmittance and diffusivity were studied and compared with the theoretical values. The results show that：the refractive indexes of polysiloxane microspheres and Poly(methyl methacrylate) are well matched, the contradiction between light transmittance and diffusivity can be solved, and the double requirements of high transmittance and haze can be achieved. When the mean diameter of microspheres is 5 μm, doping concentration is 0.6wt%, total light transmittance of light scattering materials with the thickness of 1 mm is 88.5%, and diffusivity is 89.5%. Furthermore, in the visible light wavelength, total transmittance is almost independent from wavelength. The change of diffusivity with the wavelength of light source can also be minimized with appropriate particle diameter, and wavelength dispersive can be avoided effectively.The experimental data and theoretical simulation results are very consistent..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 6, 723 (2012)
Preparation and Properties of the ZnO Nanocombs
WANG Aihua, L Linxia, SONG Haizhen, SONG Jinfan, BAO Tmurbagan, and LU Cheng
The ZnO nanocombs have been successfully synthesized on Si (111) substrates with different substrate placed conditions by thermal evaporation method. The XRD, SEM, specrophotometer and fieldemission testing device are used to investigate the morphology, structure, photoluminescence and field emission properties of theThe ZnO nanocombs have been successfully synthesized on Si (111) substrates with different substrate placed conditions by thermal evaporation method. The XRD, SEM, specrophotometer and fieldemission testing device are used to investigate the morphology, structure, photoluminescence and field emission properties of the ZnO nanocombs. XRD results indicates that both of the two samples under different substrate placed conditions(A:horizontal and B:vertical)belong to polycrystalline hexagonal structure. SEM results show that both of the two samples have nanocomb structure, but the size and the surface morphology of the nanocombs change with the different substrates placed conditions. The nanocombs in sample B are smaller and uniform. The room temperature photoluminescence(PL) spectra results show that the UV emission peak of the sample B appears blueshift in comparison to that in sample A, and the ratio of the UV emission peak to the visible emission peak in sample B is larger, indicating the high crystallization quality. Besides, The field emission test results show that the field emission of the both two samples conduct through the electronic tunnel effect, and the field emission performance of sample B is better..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 6, 728 (2012)
Extraction of Phaseshifting Value Based on Random Phase Modulation in Digital Holography
GONG Qiong, QIN Yi, MA Maofen, and L Xiaodong
An approach is proposed to determine the phaseshifting value in phaseshifting digital holography. By employing a random phase plate behind the object, we successfully made the phase distribution of the object on the holography plane a spatially approximation random distribution. Then an algorithm utilizing this charaAn approach is proposed to determine the phaseshifting value in phaseshifting digital holography. By employing a random phase plate behind the object, we successfully made the phase distribution of the object on the holography plane a spatially approximation random distribution. Then an algorithm utilizing this character to extract phaseshifting value is proposed. Computer simulations indicate that the extracted phaseshifting value is very close to the predetermined, and the relatively error is less than 0.1%. At the same time, by comparing the calculation results with and without the random phase plate, we find that the phase distribution of an object has some correlation after diffraction..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 6, 732 (2012)
Extraction of Particle Axial Position From Inline Digital Holograms Based on HilbertHuang Transform
ZHAO Xiaojuan, CEN Yuting, ZHENG Chujun, and HAN Peng
In particle digital holography, the process of determing focal distance is cumbersome and complex using traditional numerical reconstruction methods. Based on HilbertHuang transform, a method for detecting axial position of particle from inline digital hologram is presented. The radial intensity distribution of singlIn particle digital holography, the process of determing focal distance is cumbersome and complex using traditional numerical reconstruction methods. Based on HilbertHuang transform, a method for detecting axial position of particle from inline digital hologram is presented. The radial intensity distribution of single particle hologram is transformed by empirical mode decomposition which results in several intrinsic mode functions. The particle position can be determined by using liner regression of the first intrinsic mode function′s Hilbert spectrum. The validity and reliability are demonstrated by the theoretical simulation and experiments. Since it does not need to reconstruct the hologram, this method is expected to be used in real time digital particle hologram analysis..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 6, 737 (2012)
Realization of Biconjugate Gradient Stabilized Decoding Algorithm of Wavefront Coding System Based on the TMS320DM642
SUI Yuanming, LIU Peng, LIU Qinxiao, ZHANG Lei, YU Feihong, and CHEN Yangping
Wavefront coding system is a new type of opticaldigital twostep imaging system. The cubic phase mask is used to get asymmetric point spread function and the intermediate blurred image which nearly the same in a considerable depth of field. Combined with spatial domain optical imaging modeland kronecker product, an imWavefront coding system is a new type of opticaldigital twostep imaging system. The cubic phase mask is used to get asymmetric point spread function and the intermediate blurred image which nearly the same in a considerable depth of field. Combined with spatial domain optical imaging modeland kronecker product, an image restoration algorithm which based on the BiCGSTAB(BiConjugate Gradient Stabilized) and antireflective boundary conditions was used in the digital decoding part of the wavefront coding system. This algorithm have advantages such as small computing amount, high computing speed and nearly no boundary effect. The new algorithm was optimized and transplanted with the characteristics of parallel computing for the platform of TMS320DM642.The whole platform consists of image capture module, image display module and external memory module. By a specially designed optical system, the experiment imaging the human and object with the object distance of 1 m, 5 m and 10 m. From the experimental result of middle blurred images, the effect of this new algorithm on the platform of TMS320DM642 is good, and it gives the possibility to realization of the truly portable and practical of the wavefront coding system..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 6, 744 (2012)
Image Denoising Using Mixed Statistical Model in Nonsubsampled Contourlet Transform Domain
YIN Ming, and LIU Wei
A novel image denoising algorithm based on nonsubsampled Contourlet transform domain is proposed. First, according to the correlation of nonsubsampled Contourlet transform coefficients in interscale and intrascale, nonGaussian distribution model is used to model its correlations. We propose a classification standard wA novel image denoising algorithm based on nonsubsampled Contourlet transform domain is proposed. First, according to the correlation of nonsubsampled Contourlet transform coefficients in interscale and intrascale, nonGaussian distribution model is used to model its correlations. We propose a classification standard where the coefficients are divided into important and unimportance coefficients, and generalized Gaussian distribution is used to describe the probability distribution for the important coefficients. Adaptive threshold is derived under the Bayesian theory and the best range of the parameter is found out. In order to overcome the shortcoming of the soft and hard thresholding function, then a new adjustable thresholding function is presented. Lastly, the new thresholding function is used to estimate coefficients without noise, and inverse nonsubsampled Contourlet transformation is performed to get denoised image. Experimental results show that our algorithm outperforms the other current outstanding algorithms in peak signaltonoise ratio, structural similarity and visual quality..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 6, 751 (2012)
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