Contents
2001
Volume: 21 Issue 2
30 Article(s)
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Fiber Optics and Optical Communications
A Model and Analysis of Five-Layer Optical Waveguide of Polarization Maintaining Fiber Polarizer with Metallic Coatings
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A physical model of five-layer optical waveguide with variation parameters of polarization maintaining fiber (PMF) polarizer with metallic coatings is proposed. A numerical method named adaptive zoom hill climbing method is designed to solve complex transcendental equations of multi-layer optical waveguide. The computiA physical model of five-layer optical waveguide with variation parameters of polarization maintaining fiber (PMF) polarizer with metallic coatings is proposed. A numerical method named adaptive zoom hill climbing method is designed to solve complex transcendental equations of multi-layer optical waveguide. The computing results discribe the physical mechanism of PMF polarizer with metallic coatings. Optimum design of device structure is achieved and the results of measurement are given..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 2, 142 (2001)
Effect of UV Uniform Exposure on Coupling Characteristics of Long-Period Fibre Gratings
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
UV uniform exposure can effectively vary the coupling characteristics of the annealed long-period gratings (LPGs) in hydrogen-loaded fiber. With the increase of UV exposure, the resonance wavelength shifts toward longer wavelength and resonance peak intensity increases first and then decreases. A theoretical explanatioUV uniform exposure can effectively vary the coupling characteristics of the annealed long-period gratings (LPGs) in hydrogen-loaded fiber. With the increase of UV exposure, the resonance wavelength shifts toward longer wavelength and resonance peak intensity increases first and then decreases. A theoretical explanation for this phenomenon has been given..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 2, 147 (2001)
Fourier Optics and Signal Processing
Using Optical Walsh Transformation for Feature Extraction in Image Matching
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A Novel method is proposed for realizing optical Walsh transformation to extract the most important features in images. The important features can be used in optical image matching of large capacity image library. Based on a hybrid opto-electrical image processing system with an incoherent correlator, the image matchinA Novel method is proposed for realizing optical Walsh transformation to extract the most important features in images. The important features can be used in optical image matching of large capacity image library. Based on a hybrid opto-electrical image processing system with an incoherent correlator, the image matching algorithm using optical Walsh transformation is realized successfully..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 2, 167 (2001)
A Method of Multi-Pattern Classification with Encoded Feature-MasksA Multiple Networks Fusion Approach for 3-D Ojbect Recognition from 2-D Veiws
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Based on the encoding theory and neural network optimization algorithm, a method is proposed to construct a set of encoded feature-masks to discriminate a group of patterns, and usually the group includes a lot of classes. Recognition of 26 English capital letters is as a case study.A multiple networks fusion approach Based on the encoding theory and neural network optimization algorithm, a method is proposed to construct a set of encoded feature-masks to discriminate a group of patterns, and usually the group includes a lot of classes. Recognition of 26 English capital letters is as a case study.A multiple networks fusion approach is proposed for 3D object recognition from 2D views. As the probability of correct classification is correlated with certainty of a network, a fusion method based on certainty is developed which combines the outputs from all the neural networks to improve classification performance. A multiple networks fusion structure is constructed by combining three multi-layer forward propagation network that differ from the others in internal parameters such as the number of hidden layer nodes, initial random weights et al.. The performance is compared to that of individual MLP using four different vehicles involving clean and noisy images. It is shown that multiple networks fusion has major advantages over single multi-payer forward propagation network..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 2, 173 (2001)
Discussion about Off-Focus Influence on Joint Transform Correlator for Optical Fiber Detection
[in Chinese], [in Chinese], and [in Chinese]
The spectrum sampling out of focus of joint transform correlator has been discussed from three points of view, that is, theoretical analysis, computer simulation and experiment of the detection of defects in optical fibers. The relation curves between cross-correlation intensity and off-focus distance is obtained. The The spectrum sampling out of focus of joint transform correlator has been discussed from three points of view, that is, theoretical analysis, computer simulation and experiment of the detection of defects in optical fibers. The relation curves between cross-correlation intensity and off-focus distance is obtained. The computer simulation results of joint transform correlation with different reference images and signal images in focus plane and off-focus plane respectively are demonstrated. The experimental results of detection for defects in fiber with different optical fibers in focus plane and off-focus plane are given..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 2, 181 (2001)
A New Method for Astronomical Image Reconstruction in Spatial Region: Iterative Shift-and-Add Technique
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
In astronomical speckle imaging, based on a new datum point for shifting that is the maximum value point of the autocorrlation of the object, a new astronomical image reconstruction method working in spatial region——iterative shift-and-add technique (ISA) is advanced. It can be applied to remove atmospheric turbulence In astronomical speckle imaging, based on a new datum point for shifting that is the maximum value point of the autocorrlation of the object, a new astronomical image reconstruction method working in spatial region——iterative shift-and-add technique (ISA) is advanced. It can be applied to remove atmospheric turbulence influence effectively and thus the astronomical imaging with the diffraction-limited resoulition of the telescope will be achieved. After describing the principle of the method, the image reconstruction experiments of some astronomical obejcts are given..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 2, 186 (2001)
Instrumentation, Measurement and Metrology
Analysis and Calculation of Throughput of the Polarization Interference Imaging Spectrometer
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Shearing and imaging principle of the polarization interference imaging spectrometer (PIIS) are presented. Throughput of the PIIS is analyzed and calculated, the changing relation of throughput with deviation is derived under polarizer's polarized direction deviating from the ideal direction. Throughput value in thShearing and imaging principle of the polarization interference imaging spectrometer (PIIS) are presented. Throughput of the PIIS is analyzed and calculated, the changing relation of throughput with deviation is derived under polarizer's polarized direction deviating from the ideal direction. Throughput value in the maximum modulation depth is given. The PIIS has simple structure and no moving parts, high pass through rate of energy. It shows the advantages of ultra-compact, stationary, wide view of field, high throughput and modulation depth. It is more suitable for remote sensing of aviation and aerospace, field operation and weak signal detection..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 2, 192 (2001)
High-Throughput Computed-Tomography Imaging Spectrometer and Its Simulated Experiment
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The principles and configuration of the high-throughput computed-tomography imaging spectrometer are introduced. Three kinds of dispersers (including direct-view prism) are designed and an iterative reconstruction algorithm is described. Some simulated experiments are made, and the spectral image consisting of 61×The principles and configuration of the high-throughput computed-tomography imaging spectrometer are introduced. Three kinds of dispersers (including direct-view prism) are designed and an iterative reconstruction algorithm is described. Some simulated experiments are made, and the spectral image consisting of 61×61 spatial pixels and 13 spectral bands are obtained. The simulation results show that the theorem is correct, and that the reconstruction algorithm is efficient, convergent and reliable..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 2, 198 (2001)
Development of a Cryogenic Optical System
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The development of a cryogenic optical system is presented including the system design, manufacturing and cryogenic test at near liquid nitrogen temperature. The test results show that there is little wavefront error difference between the optical system at room temperature and cooled to 100 K. In both cases the opticaThe development of a cryogenic optical system is presented including the system design, manufacturing and cryogenic test at near liquid nitrogen temperature. The test results show that there is little wavefront error difference between the optical system at room temperature and cooled to 100 K. In both cases the optical system all can achieve diffraction limited imaging quality..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 2, 202 (2001)
Tagging Procedures of Raman Excitation Plus Laser Induced Electronic Fluorescence Flow Velocimetry
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The Raman excitation plus laser induced electronic fluorescence air flow velocimetry system is constructed. The second harmonics of Nd∶YAG laser and stimulated Raman scattering in O2 are employed as “tagging” laser source. The tagged line was interrogated with an ArF excimer laser. The laser-induced fluorescence imagesThe Raman excitation plus laser induced electronic fluorescence air flow velocimetry system is constructed. The second harmonics of Nd∶YAG laser and stimulated Raman scattering in O2 are employed as “tagging” laser source. The tagged line was interrogated with an ArF excimer laser. The laser-induced fluorescence images from tagged lines in O2 and air are captured by an intensity-CCD Camera. The velocity measurement of O2 jet is carried out..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 2, 206 (2001)
Relationship between Laser Speckle Correlation and Displacement
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The relationship between laser speckle correlation and displacement is studied by the statistic theory and experiment. The theoretical and experimental results agree well. The results offer a guide to the speckle correlation measurement.The relationship between laser speckle correlation and displacement is studied by the statistic theory and experiment. The theoretical and experimental results agree well. The results offer a guide to the speckle correlation measurement..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 2, 211 (2001)
Lasers and Laser Optics
Ray-Pulse Matrix on the Spatial and Temporal Characteristics of the Femtosecond Pulse in the Kerr MediumInvestigation of Simultaneous Oscillation of Self-Terminating and Recombination Laser
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
With the temporal components and spatial components combined in one matrix so that the temporal elements include spatial variables and vice versa. The ray matrix which describes the spatial and temporal characteristics of femtosecond pulse in the Kerr medium is obtained.The simultaneous oscillations of calcium ion recoWith the temporal components and spatial components combined in one matrix so that the temporal elements include spatial variables and vice versa. The ray matrix which describes the spatial and temporal characteristics of femtosecond pulse in the Kerr medium is obtained.The simultaneous oscillations of calcium ion recombination and self-terminating laser is analysed theoretically and obtained in the experiment for the first time through improving discharge circuit and cavity structure. The maximum average output power reaches 70 mW. The photo-electro pulse waveforms is measured and discussed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 2, 158 (2001)
Study on the Threshold in Ytterbium-Doped Fiber
[in Chinese], and [in Chinese]
On the basis of the population rate equation, energy levels and spectrum characteristics of Yb3+ in host and McCumber relation, the formulas describing pump threshold power are deduced for Yb3+-doped fiber laser. The factors affecting pump threshold power are analysed. Related experiments have been conducted. Theory arOn the basis of the population rate equation, energy levels and spectrum characteristics of Yb3+ in host and McCumber relation, the formulas describing pump threshold power are deduced for Yb3+-doped fiber laser. The factors affecting pump threshold power are analysed. Related experiments have been conducted. Theory are in accord with experimental results..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 2, 164 (2001)
Materials
Luminescence Properties of Nanocrystalline ZnS∶Mn in SiO2 Aerogels
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Nanocrystalline ZnS∶Mn contained SiO2 aerogels were prepared by sol-gel process. The sizes of the nanocrystals were estimated by X-ray diffraction and caculated from the emission spectra of the aerogels. The excitation, emission and time-resolved spectra of the aerogels were investigated. Experiments show high luminescNanocrystalline ZnS∶Mn contained SiO2 aerogels were prepared by sol-gel process. The sizes of the nanocrystals were estimated by X-ray diffraction and caculated from the emission spectra of the aerogels. The excitation, emission and time-resolved spectra of the aerogels were investigated. Experiments show high luminescence efficiency and short decay time of Mn2+ in nanocrystalline ZnS. The decay time is one order magnitude less than that in bulk ZnS crystal..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 2, 215 (2001)
Third-Order Nonlinearities of Ag2S Nanoparticles Capped with 2,2’-Bipyridine and Hexametaphosphate
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Two kinds of Ag2S nanoparticles with different surface-capping molecules (2,2’-bipyridine and hexametaphosphate ) were prepared by colloidal chemical method. Their third-order nonlinear optical properties have been studied in non-resonance region of one photon via degenerate four-wave mixing in phase conjugation geometTwo kinds of Ag2S nanoparticles with different surface-capping molecules (2,2’-bipyridine and hexametaphosphate ) were prepared by colloidal chemical method. Their third-order nonlinear optical properties have been studied in non-resonance region of one photon via degenerate four-wave mixing in phase conjugation geometry. The results show that two-photon resonant process greatly contributes to the third-order nonlinearities of Ag2S nanoparticles. It is also found that the third-order susceptibicities χ(3) are intensively subjected to the surface-capping molecules. This phenomenon is interpreted in terms of local field enhancement effect related to refractive index of the media around nanoparticles..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 2, 218 (2001)
Nonlinear Optical Properties of C60 Derivatives
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The nonlinear optical properties of a series of C60 derivatives with different substituents are reported. The optical limiting properties were measured using the second harmonic of a Q-switched Nd∶YAG at 532 nm, the third-order optical nonlinearities of C60 derivatives in solution were studied by nanosecond degenerate The nonlinear optical properties of a series of C60 derivatives with different substituents are reported. The optical limiting properties were measured using the second harmonic of a Q-switched Nd∶YAG at 532 nm, the third-order optical nonlinearities of C60 derivatives in solution were studied by nanosecond degenerate four-wave-mixing(DFWM) experiment. The values of the third-order hyperpolarizabilities γ(3) and the third-order nonlinear optical susceptibilities χ(3) of C60 derivatives were obtained, respectively. Experimental results show that different substituents have different effects on the nonlinear optical properties of C60 derivatives..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 2, 222 (2001)
Absorption of Excited State of Cr4+∶YAG Crystal
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Cr4+∶YAG is studied as a saturable absorber of 1064 nm laser. The dynamic process of excited state absorption (ESA) is described by using rate equations, with the crystal interacting with low or high power laser. The function about intensity varying with the transmission derived by rate equations is demonstrated by expCr4+∶YAG is studied as a saturable absorber of 1064 nm laser. The dynamic process of excited state absorption (ESA) is described by using rate equations, with the crystal interacting with low or high power laser. The function about intensity varying with the transmission derived by rate equations is demonstrated by experiment. Therefore, it is shown that the Q switching is possible and can be optimized by using the ESA of the crystal..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 2, 225 (2001)
Shallow-Level Center in Photorefractive Cu∶KNSBN Crystal
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The experiments and theoretical analysis on the erasure process of the grating, light-induced absorption and thermal activation demonstrated that there exists a shallow-level center besides a deep-level center in the Cu-doped KNSBN crystal. It was considered to be oxide vacancy formed during growth of the crystal. The The experiments and theoretical analysis on the erasure process of the grating, light-induced absorption and thermal activation demonstrated that there exists a shallow-level center besides a deep-level center in the Cu-doped KNSBN crystal. It was considered to be oxide vacancy formed during growth of the crystal. The gain of the two-wave mixing (TWM) reaches its maximum value when the temperature of crystal is about 360 K. The relationship between the gain of TWM and the crystal temperature was explained through two-center two-grating model. The function of the shallow-level center in photorefraction was discussed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 2, 228 (2001)
Nonlinear Optics
Direct Measurement of Type Ⅰ Phase-Matching Curve of KTP Crystal Using Sphere Method
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Phase-matched type Ⅰ second-harmonic generation in a φ10 mm KTP crystal sphere using a 35 picosecond pulse as pump laser is reported. The type Ⅰ phase-matching (PM)curve of KTP crystal is measured directly according to the SHG conversion efficiency, and the corresponding nonlinear optical coefficient is calculated. By Phase-matched type Ⅰ second-harmonic generation in a φ10 mm KTP crystal sphere using a 35 picosecond pulse as pump laser is reported. The type Ⅰ phase-matching (PM)curve of KTP crystal is measured directly according to the SHG conversion efficiency, and the corresponding nonlinear optical coefficient is calculated. By comparison of the experimental PM curve with the theoretical PM curves calculated from six Sellmeier’s equations, it is found that the equation given by Vanherzeele is the best one..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 2, 134 (2001)
Amendatory Calculation of the Acceptance Parameters in Three-Wave Interactions
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The traditional method of calculation for the acceptance parameters by Taylor expansion in three wave interactions is only suitable for the condition of small acceptance parameters. The accurate calculation method of the acceptance parameters by means of definition is given. Through numerical calculation some values ofThe traditional method of calculation for the acceptance parameters by Taylor expansion in three wave interactions is only suitable for the condition of small acceptance parameters. The accurate calculation method of the acceptance parameters by means of definition is given. Through numerical calculation some values of acceptance parameters are corrected, and some super wide acceptance wavelength bands of SHG in nonlinear crystals are found, which are almost tens times larger than that calculated by traditional method. It suggests the possibility of obtaining super acceptance spectral bands in 1 cm long crystal for SHG..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 2, 139 (2001)
Optical Devices
Precision Angle Sensor and Its Calibration Techniques
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A high-precision angle sensor and a new method for calibrating precision angle sensor absolutely without any accurate reference instruments are described. Two angle sensors with compensate devices which compensating thermal drift of the light source are developed and calibrated by themselves. The measurement ranges of A high-precision angle sensor and a new method for calibrating precision angle sensor absolutely without any accurate reference instruments are described. Two angle sensors with compensate devices which compensating thermal drift of the light source are developed and calibrated by themselves. The measurement ranges of two angle sensors are 180″, and the resolutions of two angle sensors are 0.003″ and 0.004″, respectively. The repeatability error of the evaluated mean sensitivity was improved to 0.015% by compensating device. The repeatability of the calibrated linearity error was reduced to 0.015″..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 2, 232 (2001)
Fast Processing of Fourier Modal Method for Perpendicularly Crossed Surface-Relief Binary-Period Gratings
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The “inverse rule” Fourier expansion is used to enhance the convergence of perpendicularly crossed surface-relief binary-period gratings. The reflection-transmission-coefficient-matrix (RTCM) algorithm used in single-period gratings is extended to perpendicularly crossed binary-period gratings. The symmetry and diagonaThe “inverse rule” Fourier expansion is used to enhance the convergence of perpendicularly crossed surface-relief binary-period gratings. The reflection-transmission-coefficient-matrix (RTCM) algorithm used in single-period gratings is extended to perpendicularly crossed binary-period gratings. The symmetry and diagonal period are well used, keeping certain computational accuracy and steady, to increase the speed of computation to tens of times, so that the calculation of such problem can be done by PC instead of large computers..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 2, 236 (2001)
Spatial Photon Distribution of Undulator Radiation and Transmission Photon Flux Through Aperture
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Theoritical discussion of spatial photon distribution of undulator radiation is presented simply, and the result of spatial photon distribution of SSRF U3.65 is given by the method of numerical simulation. According to the spatial photon distribution, the selecting aperture dimension is decided, and transmission photonTheoritical discussion of spatial photon distribution of undulator radiation is presented simply, and the result of spatial photon distribution of SSRF U3.65 is given by the method of numerical simulation. According to the spatial photon distribution, the selecting aperture dimension is decided, and transmission photon flux and power through aperture is calculated..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 2, 242 (2001)
Method for Improving Performance of Infrared Detector by Micro-Optical Lens Array
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The mechanism for improving performance of infrared detector using micro optical method is studied. A germanium microlens array was coupled to a 180 unit infrared HgCdTe focal plane array detector. The detectivity of the coupled device was increased to 2.8-fold. As an objective standard, the optical coupling efficiencyThe mechanism for improving performance of infrared detector using micro optical method is studied. A germanium microlens array was coupled to a 180 unit infrared HgCdTe focal plane array detector. The detectivity of the coupled device was increased to 2.8-fold. As an objective standard, the optical coupling efficiency is proposed to evaluate the quality of micro optical concentrator and the coupled method. The cooling shield effect caused by microlens array, which is useful to limit the background radiation was also discussed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 2, 246 (2001)
Physical Optics
Monte Carlo Simulations for Time Characteristics of Light Propagation in Scattering Medium
[in Chinese], [in Chinese], and [in Chinese]
Monte Carlo Simulations for time characteristics of ultrashort pulse light propagation in the skin four-striated scattering medium are presented. Variations of diffusive intensity with the radial distance and angle at different time are given. The frequency-domain results of time response of surface diffusive intensityMonte Carlo Simulations for time characteristics of ultrashort pulse light propagation in the skin four-striated scattering medium are presented. Variations of diffusive intensity with the radial distance and angle at different time are given. The frequency-domain results of time response of surface diffusive intensity are obtained by using Fourier transformation. The results show that the diffusive intensity changes with time to the extent of magnitude and its time-resolution is in the order of ps, so the detector with large dynamic range and ps time-resolution is needed. The results from the frequency-domain analyses show that the amplitude and phase have significant changes at very high frequency, but the realization of the detection is not feasible..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 2, 155 (2001)
Quantum Optics
Measurements and Analyses of Light Frequency Shift in a Small Optically Pumped Cesium Beam Frequency Standard
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
In the experimental system of diffused laser light field pumped sharp angle incidence laser light probing small cesium beam frequency standard, the light frequency shift (mainly the AC Stark shift) caused by diffused laser light comes from the diffused laser light field, and the light frequency shift caused by fluorescIn the experimental system of diffused laser light field pumped sharp angle incidence laser light probing small cesium beam frequency standard, the light frequency shift (mainly the AC Stark shift) caused by diffused laser light comes from the diffused laser light field, and the light frequency shift caused by fluorescent light comes from the pumping region have been measured carefully. The measured results were analyzed and compared with the calculated results. The results proved that, under normal working conditionin, the light frequency shift caused by diffused laser light is less than -2×10-13, the light frequency shift caused by fluorescent light is about 0.8×10-13, such results are acceptable for a small optically pumped cesium beam frequency standard..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 2, 129 (2001)
Rapid Communications
Fluorescence Characteristics of Electron Trapping Material Eu,Sm∶CaS
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The fluorescence excitation and emission spectrum of electron trapping material Eu,Sm∶CaS at room temperature are investigated. The excitation spectrum consists of four emission bands, which are assigened to 4f6→4f55d transition of Eu2+ ion and fundamental absorption of CaS. The fluorescence emission spectrum excited aThe fluorescence excitation and emission spectrum of electron trapping material Eu,Sm∶CaS at room temperature are investigated. The excitation spectrum consists of four emission bands, which are assigened to 4f6→4f55d transition of Eu2+ ion and fundamental absorption of CaS. The fluorescence emission spectrum excited at visible light consists of one strongest broaden emission band and two weakest narrow emission bands. While in the spectrum excited at ultraviolet light, not only the three emission bands but also seven stronger narrow emission bands are observed, which are assigned to 4f65d→4f7 transision of Eu2+, f→f transition of Sm3+, f→f transision of Eu3+ respectively. It is found that the fluorescence emission strength of Eu2+ ion is apparent stronger than that of Sm3+ as the activator concentrations are proper..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 2, 250 (2001)
A Mirror-Dispersion-Controlled and Self-Started Femtosecond Ti∶Sapphire Laser
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A Gires-Tounois negative dispersion mirrors is designed and optimized. A mirror-dispersion controlled self-started femtosecond intercavity Ti∶sapphire laser is operated by using this mirror together with a semiconductor saturable-absorber mirror.A Gires-Tounois negative dispersion mirrors is designed and optimized. A mirror-dispersion controlled self-started femtosecond intercavity Ti∶sapphire laser is operated by using this mirror together with a semiconductor saturable-absorber mirror..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 2, 253 (2001)
Two Channel Self-Focusing Matched Filter by Computer-Generated Hologram
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A two-channel matched filter using computer-generated holograph is introduced. On the basis of CGH, it can encode two objects simultaneously by adding negative quadratic phase factor on the conjugate Fourier spectrum of one object and adding positive quadratic phase factor on the Fourier spectrum of the other. The expeA two-channel matched filter using computer-generated holograph is introduced. On the basis of CGH, it can encode two objects simultaneously by adding negative quadratic phase factor on the conjugate Fourier spectrum of one object and adding positive quadratic phase factor on the Fourier spectrum of the other. The experimental results, which are consistent with theory, are given..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 2, 255 (2001)
Thin Films
Measuring Weak Absorptance of Thin Film Coatings by Surface Thermal Lensing Technique
[in Chinese], [in Chinese], and [in Chinese]
A novel sensitive and simple scheme, referred to as the surface thermal lensing technique, has been introduced for detecting and analyzing the thermal waves to get information about weak absorptance of optical coatings. Its diffraction theory is presented briefly. Several samples for the Robin absorptance measurements A novel sensitive and simple scheme, referred to as the surface thermal lensing technique, has been introduced for detecting and analyzing the thermal waves to get information about weak absorptance of optical coatings. Its diffraction theory is presented briefly. Several samples for the Robin absorptance measurements have been tested using this method, and the measurement results have been analyzed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 2, 150 (2001)
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