Contents
2006
Volume: 26 Issue 4
32 Article(s)
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Atmospheric Optics and Oceanic Optics
Time-averaging Effects for Atmospheric Scintillation in Atmospheric Optical Communication
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Based on time-averaging effects for atmospheric scintillation, extending photoelectric detector's exposure time is one of the effective ways to mitigate the effect of atmospheric scintillation on the link of atmospheric optical communication. Based on the Kolmogorov spectrum, the expressions are derived for time-avBased on time-averaging effects for atmospheric scintillation, extending photoelectric detector's exposure time is one of the effective ways to mitigate the effect of atmospheric scintillation on the link of atmospheric optical communication. Based on the Kolmogorov spectrum, the expressions are derived for time-averaging factors associated with atmospheric scintillations of unbounded plane wave and spherical wave, in the weak turbulence regime. Approximate expressions of the time-averaging factors for small- and large-aperture receivers are provided by use of geometrical optics approximation, respectively. When the aperture is much larger than Fresnel scale, approximate expressions differ from exact numerical results by less than 6% in the case of plane wave and 3% for spherical wave. Results show that the strength of time-averaging effects goes up along with the aperture decrease, and the effect of Fresnel scale on time-averaging effects weakens along with the increase of the aperture..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 4, 481 (2006)
Performance Analysis for Fine Tracking Loop for Adaptive Optics System with Closed-Loop Residual Tilt Data
[in Chinese], [in Chinese], and [in Chinese]
In an adaptive optical system, the object tracking error primally censists of the tracking error induced by the incompletely compensated atmospheric turbulence and the telescope vibration and the tilt noise error. A new method with the use of closed-loop residual tilt data is proposed to evaluate the tilt noise error, In an adaptive optical system, the object tracking error primally censists of the tracking error induced by the incompletely compensated atmospheric turbulence and the telescope vibration and the tilt noise error. A new method with the use of closed-loop residual tilt data is proposed to evaluate the tilt noise error, the tracking error due to the atmospheric turbulence and the vibration of the telescope,and the residual tracking error. This method is used to analyze the fine tracking loop performance of the 61-element adaptive optical system..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 4, 487 (2006)
Research of Ultrahigh-Order Modes in Double Metal-Cladding Optical Waveguide with Submillimeter Scale
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
An optical glass slab, which is coated with two metal films with different thickness on both sides, is used to form a new type of ultrathick double metal-cladding optical waveguide with submillimeter-scale. Excitation of the ultrahigh-order modes are implemented by employing the free-space coupling technique. Based on An optical glass slab, which is coated with two metal films with different thickness on both sides, is used to form a new type of ultrathick double metal-cladding optical waveguide with submillimeter-scale. Excitation of the ultrahigh-order modes are implemented by employing the free-space coupling technique. Based on the unusual features of the ultrahigh-order modes, wavelength-sensitive and polarization-insensitive, ultra-narrow bandwidth filtering (0.08 nm) and comb filtering (channel spacing 100 GHz) with tunable, low loss (0.5 dB) and polarization-insensitive operation capabilities are demonstrated experimentally..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 4, 497 (2006)
Fabrication of Single-Mode Fiber Wavelength Division Multiplexer by Using Improved Fused Biconical Taper Method
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The influences of correlative parameters in the process of fabricating fused biconical taper fiber wavelength division multiplexer on the minimum channel spacing are studied, and an improved device for fused biconical taper is designed according to the conclusion obtained by numerical simulation, which has an electric The influences of correlative parameters in the process of fabricating fused biconical taper fiber wavelength division multiplexer on the minimum channel spacing are studied, and an improved device for fused biconical taper is designed according to the conclusion obtained by numerical simulation, which has an electric strip heater with long uniform heating area as the heating unit. The coupling length is lengthened obviously by using the improved device, and the limitation of conventional drawing method to the reachable minimum channel spacing of fused biconical taper fiber wavelength division multiplexer is broken. A preliminary experiment result shows that the minimum channel spacing reaches 3.01 nm..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 4, 501 (2006)
Fiber Optics and Optical Communications
Interactions of Solitons in Dispersion Compensation Fiber Nonlinear Communication System
[in Chinese], and [in Chinese]
The effect of adjacent solitons interaction on the transmission property of solitons is studied in the nonlinear optical communication dispersion compensation system by using variational method and virial theorem. The results show that, the two solitons attract each other and then repel with periodical collision law, aThe effect of adjacent solitons interaction on the transmission property of solitons is studied in the nonlinear optical communication dispersion compensation system by using variational method and virial theorem. The results show that, the two solitons attract each other and then repel with periodical collision law, and the bound state is formed, in the common single-mode fiber with phase matching and equal amplitude injection. But under the same condition, the solitons do not collide in dispersion compensation fiber. In dispersion compensation fiber, with phase mismatch and equal amplitude injection, the solitons leave each other; with phase matching and unequal amplitude injection, if the initial positional interval is small, a relatively large initial amplitude difference is necessary for the transmission of solitons..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 4, 491 (2006)
Image Processing
Image Segmentation Using the Maximum Entropy of the Two-Dimensional Bound Histogram
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The concept of the two-dimensional bound histogram (TDBH) is proposed. It is the two-dimensional histogram bound by some prior knowledge, and it can make some image processing methods simple and feasible. Furthermore, an image segmentation method based on the TDBH is presented. In the method, the bound set of an image The concept of the two-dimensional bound histogram (TDBH) is proposed. It is the two-dimensional histogram bound by some prior knowledge, and it can make some image processing methods simple and feasible. Furthermore, an image segmentation method based on the TDBH is presented. In the method, the bound set of an image and its corresponding TDBH are constructed, and the gray-level threshold for segmentation is determined according to the maximum entropy of the TDBH. To show the validity of the method, it is used in segmenting of the image of a small underwater target. The image segmentation method based on the maximum entropy of the one-dimensional bound histogram (ODBH) is also used. The results show that the former, the proposed method, has better antinoise performances and segmental effects than the latter. The concept of the TDBH is significant in theory and engineering. The proposed method is applicable to the image where there is some prior knowledge..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 4, 506 (2006)
Optimized Design of Morphological Improved Top-Hat Filter Based on Improved Genetic Algorithms
[in Chinese], and [in Chinese]
Toward detection of feeble moving infrared spot target, improved Top-Hat morphological filtering operator is presented based on improved genetic algorithms. The optimized improved Top-Hat morphological filter restrains background and noise. And the genetic algorithm is improved with new interval discretization code andToward detection of feeble moving infrared spot target, improved Top-Hat morphological filtering operator is presented based on improved genetic algorithms. The optimized improved Top-Hat morphological filter restrains background and noise. And the genetic algorithm is improved with new interval discretization code and adaptive master-slave crossover and mutation operator. The optimized morphological filter based on global search has better filtering and time performance. To different signal to noise ratio (SNR) spot targets, the adaptive threshold is adopted for detection. Experimental results show that the detection probability of complicate images (RSN≈2) can reach more than 70% with false alarm no more than 5%. Compared with fixed Top-Hat filter, the detection probability improves nearly by 10%. Also compared with traditional Top-Hat morphological filter optimized by classical genetic algorithms, the detection probability is improved by 4%..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 4, 510 (2006)
Features Tracking Algorithm for Video Stabilization
[in Chinese], and [in Chinese]
A video stabilization algorithm is presented, which has the advantages of low computation cost, high accuracy and robustness. It consists of two parts: (1) global motion estimation is performed based on two-dimensional motion model of feature points set. The feature window with each selected feature point as the centerA video stabilization algorithm is presented, which has the advantages of low computation cost, high accuracy and robustness. It consists of two parts: (1) global motion estimation is performed based on two-dimensional motion model of feature points set. The feature window with each selected feature point as the center is matched and then the corresponding points are obtained. The feature set has a stable structure, and the relative positions of all points are stable. So distance invariant criterion is proposed to check the feature matching, keep global coherence of all local motions and produce the global motion vector of the feature points; (2) a self-adaptive average filtering is applied to exclude the influence of the camera dithering. The average filter can smooth out the high frequency dithering effectively and adjust the window length automatically according to dithering frequency to prevent overstabilization or understabilization. Experimental results show that the algorithm can effectively reduce the influence of unwanted camera rotation and translation dithering..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 4, 516 (2006)
Imaging Systems
Design of Two-Dimensional Arrays Used in Coded Aperture Imaging by Means of DIRECT Global Optimization Algorithm
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Two-dimensional arrays are the key components used in the coded aperture imaging, and directly influence the quality of reconstructed images. Unfortunately, up to now, there is not a sort of two-dimensional arrays with fine property of tomographic imaging and high photon collection rate. The authors use a new global opTwo-dimensional arrays are the key components used in the coded aperture imaging, and directly influence the quality of reconstructed images. Unfortunately, up to now, there is not a sort of two-dimensional arrays with fine property of tomographic imaging and high photon collection rate. The authors use a new global optimization method, DIRECT algorithm, to design two-dimensional arrays, which is very useful when the object function is a “black box” and has a faster convergence rate than others. The goal is designing a sort of arrays with max sidelobe of their autocorrelation function no more than 1 and the filling rate as high as possible. Theoretical analysis and experimental results prove that the arrays possess better property of tomographic imaging and higher photon collection rate than the existing arrays..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 4, 522 (2006)
A Novel Liquid Crystal Phase Modulator for the Optical Imaging System
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A novel liquid crystal phase modulator (LCPM) of 2D liquid crystal array with parallel alignment was fabricated. And experiments of Zernike polynomial production and distorted wavefront modulation were conducted on the Zygo interferometer with the LCPM. The wavefront profiles of the first 2nd to 8th Zernike polynomial A novel liquid crystal phase modulator (LCPM) of 2D liquid crystal array with parallel alignment was fabricated. And experiments of Zernike polynomial production and distorted wavefront modulation were conducted on the Zygo interferometer with the LCPM. The wavefront profiles of the first 2nd to 8th Zernike polynomial were produced successfully. Sixteen Zernike polynomials were used to modulate the distorted wavefront, the peak-to-valley value (PV) was improved from 0.831λ before modulation to 0.444λ after that, root means square (RMS) from 0.181λ to 0.066λ, and Strehl ratio (SR) from 0.257 to 0.844. The results indicated that the quality of imaging of optical systems was greatly improved when the parallel alignment LCPM is used to modulate the distorted wavefront..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 4, 527 (2006)
Calibration Method for Non-Uniformity between Multiple Images from a High-Speed Multi-Frame CCD Camera
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
For the high-speed multi-frame camer used to capture time-resolved sequence images, the main image processing includes geometric distortion calibration,image pixel position arrangement, flat-field correction for photo-response non-uniformity between the pixels in one image and the response calibration between differentFor the high-speed multi-frame camer used to capture time-resolved sequence images, the main image processing includes geometric distortion calibration,image pixel position arrangement, flat-field correction for photo-response non-uniformity between the pixels in one image and the response calibration between different sequence images．These processings can meet the demand not only on each image itself but also on the morphological comparison of sequence images. The image processing method developed from related methods to solve the above problems provides an effective way to calibrate the non-uniformity and correlation coefficients between images, and scan be used to acquire the uniformity of the sequence images in the multi-images system in the practical applications..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 4, 531 (2006)
Instrumentation, Measurement and Metrology
Measurement and Analysis of Spectral Response Characteristic of Transmission-Mode GaAs Photocathode before and after Indium Seal
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Spectral response characteristics of transmission-mode GaAs photocathode after high-temperature activation, low-temperature activation and indium sealed into intensifier are measured by use of the home-made prototype of spectral response measurement instrument. The results show that spectral response curve in the wholeSpectral response characteristics of transmission-mode GaAs photocathode after high-temperature activation, low-temperature activation and indium sealed into intensifier are measured by use of the home-made prototype of spectral response measurement instrument. The results show that spectral response curve in the whole response waveband decreases after indium seal, and long-wave responsibility is most obviously influenced. The long-wave response 800～815 nm decreases largely, cut-off wavelength and peak value wavelength move towards short-wave, peak response value and integral sensitivity decrease, and the final spectral response curve becomes flat. The calculation results of photocathode parameters reflect that surface escape probability decreases after indium seal, which indicates that indium seal leads to the variations of surface activation layers of photocathode, low-energy photoelectrons under long-wave are difficult to escape, and the long-wave response and sensitivity decrease accordingly. The influencing factors on the surface activation layers during indium seal are also analyzed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 4, 536 (2006)
Spectral Radiance Calibration of Deuterium Lamp Utilizing the Hefei 800 MeV Synchrotron Radiation
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The spectral radiance of transfer standard-deuterium lamp is calibrated using Hefei 800 MeV electron storage ring synchrotron radiation (HESYR) as an absolute UV-VUV spectral radiometric standard. The data processing and uncertainty analysis method of PTB is employed, in 115～300 nm the spectral radiance values of two dThe spectral radiance of transfer standard-deuterium lamp is calibrated using Hefei 800 MeV electron storage ring synchrotron radiation (HESYR) as an absolute UV-VUV spectral radiometric standard. The data processing and uncertainty analysis method of PTB is employed, in 115～300 nm the spectral radiance values of two deuterium lamps are obtained, and the overall uncertainty for D2 lamp calibration is 12.1%. A detailed analysis of the contributions to this uncertainty points out that the major part is caused by the uncertainty of the polarization properties of the radiometric instrumentation. In the range of 164～300 nm the D2 lamp absolute spectral radiant distribution obtained using HESYR China and that derived from BESSYⅡGermany have a discrepancy within ±20%. They are consistent within the given uncertainties..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 4, 541 (2006)
Ultraviolet and Vacuum Ultraviolet Spectral Radiance Standard with Synchrotron Radiation SourceX
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The characteristics of the 800 MeV electron storage ring of National Synchrotron Radiation Laboratory (NSRL, located in University of Science and Technology of China) are introduced. The theory and the method used to build spectral radiance standard with the synchrotron radiation are presented, and the spatial spectralThe characteristics of the 800 MeV electron storage ring of National Synchrotron Radiation Laboratory (NSRL, located in University of Science and Technology of China) are introduced. The theory and the method used to build spectral radiance standard with the synchrotron radiation are presented, and the spatial spectral power distribution of the synchrotron radiation source is calculated accurately. The classical theory of the synchrotron radiation and the spectral radiance luminance calibration of the deuterium lamp are related, and the spectral radiance power metrology using the synchrotron radiation as the standard source is studied extensively. The metrological beamline of NSRL with wide wave range, high luminance and accurately calculated radiance properties is presented, which can be used to calibrate the spectral radiance luminance of the deuterium lamp (1115～350 nm), and the uncertainty is analyzed. The calibration result is consistent with that of physical research institute (PTB) of Deutschland..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 4, 547 (2006)
Calibration and Data Merging of Two-Camera Phase Measuring Profilometry System
[in Chinese], [in Chinese], and [in Chinese]
A new method for merge of range data and texture based on calibrating two cameras in a world coordinate system is proposed. The overlapped zones and holes of data of the cameras are detected by use of modulation as mask. The part with specified size in the overlapped zones is used for data integration, according to theA new method for merge of range data and texture based on calibrating two cameras in a world coordinate system is proposed. The overlapped zones and holes of data of the cameras are detected by use of modulation as mask. The part with specified size in the overlapped zones is used for data integration, according to the nearest sequence number of samples in unit area. The method for merging regions where there are holes in one side and none in the another side is also introduced. Integrated region is constructed with the overapped zones by enlarging the edge of the hole. The data in all integrated zones are averaged with distance to their center line as weight number. Thus, the data transition of each side is smooth. The experimental results reveal this method is reliable and accurate..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 4, 551 (2006)
Vibration Measurements of Rough Surfaces Using an Liquid Crystal Spatial Light Modulator
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Vibration measurement, observing the holographic interference patterns of vibrating objects in real time in a period of time, is realized with a system, in which a speaker with aluminum foil is used as the vibrating object, imaging is realized with the diffuse reflection light from the raw surface of the aluminum foil,Vibration measurement, observing the holographic interference patterns of vibrating objects in real time in a period of time, is realized with a system, in which a speaker with aluminum foil is used as the vibrating object, imaging is realized with the diffuse reflection light from the raw surface of the aluminum foil, and an optically addressed liquid crystal spatial light modulator is used as the recorder. Time average interference measurement method is used in the experiment, and the vibration interference patterns of the object with different vibrating frequencies is obtained. When the vibrating frequency changes continuously, the changing process of the holographic interference patterns of the object is observed clearly, and the near-real time holographic interference patterns are gained..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 4, 557 (2006)
Lasers and Laser Optics
Research on New Type Control Mirror of Light Path and Optical Path Length for Ring Laser Gyroscope
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Because of advantages such as high stability, the cavity path length control mirror (PLCM) with a claw-disc-like actuator is widely used in ring laser gyroscope (RLG) to control its cavity legnth. But it cannot do anything to the change of the light path caused by the deformation of gyro block etc. After analyzing the Because of advantages such as high stability, the cavity path length control mirror (PLCM) with a claw-disc-like actuator is widely used in ring laser gyroscope (RLG) to control its cavity legnth. But it cannot do anything to the change of the light path caused by the deformation of gyro block etc. After analyzing the feature of the PLCM and based on it, a new control mirror with angle control ability that is called path and path length control mirror (PPLCM) is presented. The new control mirror can control not only the optical path length but also the light path with adding a set of angle control components to the PLCM. Novel grooved mirrors and angle control components are designed, and a new PPLCM with high performance is developed. Its property is tested, and the experimental results show that it has high stability (the largest deflection is less than 0.3″ in the temperature range of ring laser gyroscopy) and controlling sensitivity (more than 0.1 ″/V)..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 4, 562 (2006)
480 nm Blue Laser by Direct Frequency Doubling of Laser Diode
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A compact continuous-wave blue laser at 488 nm, with the maximum output exceeding 20 mW at the optimum work temperature of crystal 28 ℃, is demonstrated by direct frequency doubling of a laser diode (LD) with a quasi-phase matched waveguide periodically poled lithium niobate (PPLN) crystal. The size of the crystal is 8A compact continuous-wave blue laser at 488 nm, with the maximum output exceeding 20 mW at the optimum work temperature of crystal 28 ℃, is demonstrated by direct frequency doubling of a laser diode (LD) with a quasi-phase matched waveguide periodically poled lithium niobate (PPLN) crystal. The size of the crystal is 8 mm×1.4 mm×1 mm, and the waveguide section is 4.5 μm×3.5 μm, with 5.2 μm poling period. The temperature characteristic of the second harmonic generation (SHG) in the waveguide PPLN is investigated. The results show that the dependence of the waveguide PPLN crystal on the temperature is less than that of normal PPLN. Because the crystal works near the room temperature, the temperature controlling devices are simplified and the work efficiency of the whole system is improved. Based on the experiments, a compact all\|solid state 488 nm blue laser with continuous wave output is made..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 4, 567 (2006)
Experimental Investigation of the Oscillation of a Laser-Generated Cavitation Bubble Near a Solid Boundary
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The oscillation of a laser-generated cavitation bubble near a solid boundary is investigated with a home-made optical fiber sensor. The oscillogram corresponding to that the radius of the cavitation bubble expands to the maximum for 3 times is experimentally studied, based on which the maximum bubble radius and the colThe oscillation of a laser-generated cavitation bubble near a solid boundary is investigated with a home-made optical fiber sensor. The oscillogram corresponding to that the radius of the cavitation bubble expands to the maximum for 3 times is experimentally studied, based on which the maximum bubble radius and the collapse time for each oscillation cycle are determined. By combining the collapse theory of the cavitation bubble, the prolongation factor κ of the collapse time is calculated. A dimensionless parameter γ is defined as L/Rmax, where Rmax is the maximum bubble radius and L is the distance from the cavity core to the boundary. The results show that, the maximum bubble radius decreases with the increase of the oscillation time, with the rise of the laser energy Rmax and κ increase, and the rise of γ minishes κ. The polongation factor κ derived above is also valid in the infinite liquid field..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 4, 571 (2006)
Materials
Calculation of Thermal and Mechanical Effect Induced by Laser in Optical Window Materials
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The thermal-mechanical model of transparent optical materials induced by high-power continuous laser is set up and the precise resolution of transient temperature field distribution induced by laser is obtained through resolving the 3-dimensional heat conduction equation using integral-transform method. On the base of The thermal-mechanical model of transparent optical materials induced by high-power continuous laser is set up and the precise resolution of transient temperature field distribution induced by laser is obtained through resolving the 3-dimensional heat conduction equation using integral-transform method. On the base of the above analysis, the thermal stress field transient distribution induced by laser is worked out. Taking fused silica irradiated by 1.315 μm high-power chemical oxygen-iodine laser (COIL) as an example, the fused silica temperature field and thermalstress field transient distributions irradiated by COIL laser are calculated and the laser induced damage mechanism is analyzed further. The calculation result shows that the laser induced damage is mostly melt damage in the areas where temperature exceeds melt point of fused silica. Because fused silica has a fine thermal stability, the thermal stresses induced by the temperature ununiformity are small relatively. The theoretical analyzing result is in accordance with the relative experimental result, so the laser irradiation effect model proves correct..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 4, 576 (2006)
Optical Properties of Cu/AAO Nano-Array Composite Structure
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Cu/AAO nano-ordered arrays structure are prepared by using electrochemical technique, of which the photo absorption and photoluminescence (PL) properties are studied. The results show that the photo absorption and photoluminescence are very sensitive to the Cu nano-particles migrated into the AAO template, as the deposCu/AAO nano-ordered arrays structure are prepared by using electrochemical technique, of which the photo absorption and photoluminescence (PL) properties are studied. The results show that the photo absorption and photoluminescence are very sensitive to the Cu nano-particles migrated into the AAO template, as the deposition of Cu increases, the absorption band shows redshift, and the largest shift from the nearultra violet to the infrared exceeds 500 nm. Meanwhile, the photoluminescence peak presents slight blueshift, of which the intensity falls and quenches gradually. The above phenomena caused by the Cu nano-particles in the Cu/AAO composite are analyzed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 4, 581 (2006)
Temperature-Dependent Luminescence Originating from the Recombination of Excitons in Organic Light-Emitting Materials
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Based on experimental measurement and theoretical simulation, the temperature dependence of the photoluminescence (PL) of amorphous thin films of tris-(8-hydroxyquinoline) aluminum (Alq) and 4-(dicyanomethylene)-2-t-butyl-6(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB) has been studied. It is proposed that threBased on experimental measurement and theoretical simulation, the temperature dependence of the photoluminescence (PL) of amorphous thin films of tris-(8-hydroxyquinoline) aluminum (Alq) and 4-(dicyanomethylene)-2-t-butyl-6(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB) has been studied. It is proposed that three types of excitons with different charge separations are involved in the steady state PL process, which, with increasing energy, are accordingly called intra-molecule localized, intra-molecule delocalized, and inter-molecule delocalized, while the corresponding radiative decay rates are relatively low, high, and negligible, respectively. The blue shift of the DCJTB PL spectra with increasing temperature has been observed and explained. It is suggested that the temperature-dependent PL could be possibly used to evaluate the radiative and conductive characteristics of organic emitters and to distinguish whether a given material would be of molecular or semiconductor properties..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 4, 585 (2006)
Medical Optics and Biotechnology
A Study of Blood Glucose Concentration Measurement by Scattering Coefficient
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The relationship of scattering coefficient and concentration of blood glucose is discussed. The scattering coefficient of turbid media is determined by the relative refractive index of scattering particles to solvent. The variation of blood glucose concentration changes the refractive index of blood, and the scatteringThe relationship of scattering coefficient and concentration of blood glucose is discussed. The scattering coefficient of turbid media is determined by the relative refractive index of scattering particles to solvent. The variation of blood glucose concentration changes the refractive index of blood, and the scattering coefficient of the blood. It is given that the formuta to calculate the variation of scattering coefficient induced by concentration change of blood glucose concentration based on theoretical analysis, which shows that the scattering coefficient is directhy proportional to the blood gloucose concentration. The measurement accuracy of scattering coefficient relative change should attain 4.8×10-4 to satisfy the requirement of clinical use, and for Chinese, the absolute measurement precision must be higher than 6.82×10-3 mm-1. Double integrating sphere experiment is used to validate the theory. Milk is used as turbid media to observe the relationship of scattering coefficient and glucose concentration. At every wavelength the scattering coefficients are linearly changed with the glucose concentration and the linearity value is higher than 0.95. The theoretical analysis and the experimental result prove that blood glucose concentration can be measured by scattering coefficient..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 4, 591 (2006)
Analyses of Single Backscattering Spectra for a Two-Layer Scattering Medium
[in Chinese], [in Chinese], and [in Chinese]
Theoretical model of single backscattering spectra based on Mie scattering theory is established for a two-layer scattering media according to the structure characteristic of epithelium tissue. The theoretical model makes it possible to separate the singly backscattered light from the uppermost layer by subtracting theTheoretical model of single backscattering spectra based on Mie scattering theory is established for a two-layer scattering media according to the structure characteristic of epithelium tissue. The theoretical model makes it possible to separate the singly backscattered light from the uppermost layer by subtracting the depolarised component from the backscattered light. The characteristic of scattering spectra is analysed by simulation calculation when the morphological parameters, including mean diameter, distribution and relatine refractive index, change. The influences of mean diameter, distribution and relative refractive index of the particles of the uppermost layer on the single backscattering spectra curve and its amplitude of wave components of different orders are further studied by Fourier waveform analysis method. The results show that the single backscattering spectra are sensitive to the mean size, distribution and relative refractive index of the particles, which show direct influences on the amplitude, frequency of the ripple structure of spectra and the wave components of different orders. The simulation results can be used to identify and extract the characteristic of precancerous scattering spectra..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 4, 595 (2006)
Study on the Polarization Dependent Gain of Fiber Raman Amplfiers
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A set of improved nonlinear coupled-wave equations describing the properties of fiber Raman amplifiers is developed, which can be applied to calculate the polarization dependent Raman gain. The mathematical model of the Raman gain in single-mode birefringence optical fiber is presented by coupling mode theory. The equiA set of improved nonlinear coupled-wave equations describing the properties of fiber Raman amplifiers is developed, which can be applied to calculate the polarization dependent Raman gain. The mathematical model of the Raman gain in single-mode birefringence optical fiber is presented by coupling mode theory. The equivalence between the single-mode birefringence fiber Raman amplfiers excited at 45° with the fast axis by a linearly polarized pump and the practical fiber Raman amplfiers with randomly varying birefringence is discussed. A polarization dependent factor expressing the statistical properties of the polarization mode dispersion in single mode optical fibers quantitively is developed to substitute the one employed in the normal fiber Raman amplifier coupled nonlinear equations. The results of numerical simulations are accordant with the reported experimental data. The differences of the polarization dependent gains between the copropagating and counterpropagating pump are discussed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 4, 600 (2006)
Effects of Exciton-Phonon Interaction on Third-Order Nonlinear Optical Properties
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The nonlinear optical properties of the strongly coupled exciton-phonon systems are investigated theoretically without making any approximation for excitons. It is shown that the nonlinear optical absorptions and Kerr coefficients are enhanced significantly as the frequency detuning value of the signal field and the exThe nonlinear optical properties of the strongly coupled exciton-phonon systems are investigated theoretically without making any approximation for excitons. It is shown that the nonlinear optical absorptions and Kerr coefficients are enhanced significantly as the frequency detuning value of the signal field and the excition is equal to the phonon frequency, which makes clear that the strong excition-phonon interaction affects the nonlinear optical properties of the medium greatly. The numerical results and the detailed comparison also indicate that the nonlinear optical absorptions and Kerr coefficients are further magnified without making Bose approximation and the Dyson-Maleev approximation for excitons..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 4, 605 (2006)
Analysis of THz Electromagnetic Wave Output Character Based on High Performance 85mm Short Cavity Optical Parametric Oscillator
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The THz wave output with the 85 mm F-P single cavity optical parametric oscillator based on the MgO∶LiNbO3 crystal was reported. The Nd∶YAG Q-switched laser with 1064 nm was used as the pump source, and the THz wave was tuned by changing the incident angle as well as the phase matching condition. THz wave frequency canThe THz wave output with the 85 mm F-P single cavity optical parametric oscillator based on the MgO∶LiNbO3 crystal was reported. The Nd∶YAG Q-switched laser with 1064 nm was used as the pump source, and the THz wave was tuned by changing the incident angle as well as the phase matching condition. THz wave frequency can be detected with the THz interferometer and the Si bolometer, or by detecting the idle light frequency. Experimental results indicate the THz wave is 0.9～3.0 THz tunable. The peak energy output is 102.5 pJ/pulse at 1.2 THz with the pump energy of 20 mJ/pulse, pulse width of 16 ns, repetition rate of 50 Hz. THz energy output was increased when a Si-prism array was introduced to decrease THz wave's total reflection at the interface of crystal. The THz wave beam pattern along the horizontal was measured with a metal-slit-detector. The influence of diffraction effect of the Si prism array on the THz wave beam spatial profile was discussed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 4, 616 (2006)
Optical Devices
Space-Variant Fresnel Joint Transform Correlator
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A Fresnel joint transform correlator (FnJTC) is presented, here the Fourier transform in the joint (Fourier) transform correlator (JTC) is replaced by the Fresnel transform . The mathematical derivations for FnJTC are given, together with the computer simulation verifications. Compared with JTC, FnJTC is a space-varianA Fresnel joint transform correlator (FnJTC) is presented, here the Fourier transform in the joint (Fourier) transform correlator (JTC) is replaced by the Fresnel transform . The mathematical derivations for FnJTC are given, together with the computer simulation verifications. Compared with JTC, FnJTC is a space-variant system, output of which depends on the similarity of the two joint patterns in shape, the position of the reference pattern relative to the target pattern and the phase modulation of the reference pattern or the target pattern. The relation between FnJTC and fractional JTC has been described briefly..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 4, 621 (2006)
Effect of Random Growth Error on Double Half-Wave Fabry-Pérot Filter with Flat-Top Response
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
In the optical network, a filter with flat-top response can complete the quick and accurate channel optical detection with wavelength. With two Fabry-Pérot cavities coupled in series, a double half-wave filter with flat-top transmission characteristic is demonstrated. The effect of the random growth error on the tIn the optical network, a filter with flat-top response can complete the quick and accurate channel optical detection with wavelength. With two Fabry-Pérot cavities coupled in series, a double half-wave filter with flat-top transmission characteristic is demonstrated. The effect of the random growth error on the transmission performance of the double half-wave filter with flat-top response is studied, with the transmission matrix method. The simulation indicates that there appear two peaks with different height in the transmission spectra when the physical thickness difference of the two Fabry-Pérot cavities exceeds 1 nm, which illustrates the two-peak asymmetry in the transmission spectra of the tested devices. In addition, the concept of interface random undulation is used to explain why the measured bandwidth of the filter is larger than the theoretical result..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 4, 625 (2006)
Physical Optics
Electromagnetic Scattering for a Non-Spherical Aerosols with Arbitrary Shaped Beam
[in Chinese], and [in Chinese]
The electromagnetic scattering properties of spheroidal aerosols are investigated. The numerical values of the scattering intensity under arbitrary shaped beam illumination of aerosols are evaluated by using a generalized Lorenz-Mie theory. The distribution of the scattering intensity is given as the function of the poThe electromagnetic scattering properties of spheroidal aerosols are investigated. The numerical values of the scattering intensity under arbitrary shaped beam illumination of aerosols are evaluated by using a generalized Lorenz-Mie theory. The distribution of the scattering intensity is given as the function of the position of the laser beam waist. The dependence of rainbow intensity and scattering angle on ellipticity of the spheroidal aerosols is analyzed and a shift of the main peak with the increase of ratio a/b is observed. The calculation shows that in the falling process of the raindrop, the scattering intensity of all directions decreases gradually, in other words, the scattering intensity decreases and the rainbow angle expands with the rise of ellipticity of the raindrop. In the case of laser incidence, the farther of the aerosol is from the laser beam center, the weaker the scattering intensity is. With the scale parameter increasing, the oscillating frequency of the back scattering is larger than that of the forward scattering, and both of them decrease with the increase of the radius vector magnitude of the laser beam waist..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 4, 630 (2006)
Rapid Communications
ZnO Thin Films Prepared by PECVD from Mixture Sources of Metalorganic Zinc and Carbon Dioxide-Hydrogen Gas
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
ZnO films are prepared by plasma enhanced chemical vapor deposition (PECVD), using carbon dioxide-hydrogen gas and diethylzinc gas as reactant sources. Carbon dioxide reacts with hydrogen in the plasma charmer to produce oxygen source. Crystallographic properties and surface morphology of the films are characterized byZnO films are prepared by plasma enhanced chemical vapor deposition (PECVD), using carbon dioxide-hydrogen gas and diethylzinc gas as reactant sources. Carbon dioxide reacts with hydrogen in the plasma charmer to produce oxygen source. Crystallographic properties and surface morphology of the films are characterized by X-ray diffraction (XRD) and atomic force microscopy (AFM). The results indicate that the wurtzite structure of ZnO thin films with a strong c-axis orientation is successfully deposited on Si substrate. AFM images show that the grains arrange regularly and roughness of the surface is very small. A type emission peak at 380 nm of ZnO is also observed from photoluminescence (PL) spectrum..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 4, 639 (2006)
X-Ray Optics
Determination of Primary Energy Spectrum Distribution of X-Ray Tube in X-Ray Fluorescence Analysis
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A premise of X-ray fluorescence analysis is the determined acquisition of the primary energy spectral distribution emitted by the X-ray tube, and the energy spectral distribution function affects the accuracy of the final measurement greatly. An indirect approach to determine the primary energy spectral distribution ofA premise of X-ray fluorescence analysis is the determined acquisition of the primary energy spectral distribution emitted by the X-ray tube, and the energy spectral distribution function affects the accuracy of the final measurement greatly. An indirect approach to determine the primary energy spectral distribution of X-ray is derived, which includes relaying on the X-ray fluorescent intensities measured from the pure element sample of the thick target, establishing nonlinear functions with the known theoretical formula and obtaining the parameters in the parameter model through optimization. The comparison of the fluorescent intensity of the elements measured in the experiment and the theoretical value calculated with the energy spectral distribution function proves the approach valid..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 4, 634 (2006)
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