Contents
2000
Volume: 20 Issue 7
26 Article(s)
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Atmospheric Optics and Oceanic Optics
Power Spectra Analysis of the Disturbed Wavefront in Laser Beam Horizontal Atmospheric Propagation I: Wavefront Overall Tilt and Tyler Frequency
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
By using the Hartmann-Shack wavefront sensor of an adaptive optical system, power spectra density (PSD) of the atmosphere disturbed wavefront overall tilt was measured and analyzed. It is shown that the measured PSDs are different from the theoretic results of Kolmogorov turbulence given by Tyler. A method of calculatiBy using the Hartmann-Shack wavefront sensor of an adaptive optical system, power spectra density (PSD) of the atmosphere disturbed wavefront overall tilt was measured and analyzed. It is shown that the measured PSDs are different from the theoretic results of Kolmogorov turbulence given by Tyler. A method of calculating the Tyler frequency and the required control bandwidth of the fast steering mirror of an adaptive optical system from measured overall tilt PSDs was discussed too..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 20, Issue 7, 883 (2000)
Fourier Optics and Signal Processing
Optical Distortion-Invariant Image Recognition Based on the Multivariated Discriminant Analysis
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
An optical distortion-invariant image recognition method based on the multivariated statistical analysis is presented. In this approach, a set of eigenimages is first extracted from a large number of training images including various distortions by using the principal component analysis and then are used as the referenAn optical distortion-invariant image recognition method based on the multivariated statistical analysis is presented. In this approach, a set of eigenimages is first extracted from a large number of training images including various distortions by using the principal component analysis and then are used as the reference patterns to be optical correlated with the testing input image. The optical correlation results between the input image and the set of eigenimges construct a feature space, on which the discriminant analysis is performed during the training and classification process. Then the distortion-invariant recognition to the input image can be implemented quickly. The optical experimental results implemented on an incoherent optical correlator are given..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 20, Issue 7, 912 (2000)
Real-Time Recognition of Multi-Targets with Complicated Distortion Based on Cascaded Neural Networks
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Further work was done on the cascaded neural network system for muti-target recognition. Three plane models were used as targets to be recognized to imitate the real scene. It is found that the recognizing rate is lowered dramatically mostly due to complex distortions occuring in applications, which are very different Further work was done on the cascaded neural network system for muti-target recognition. Three plane models were used as targets to be recognized to imitate the real scene. It is found that the recognizing rate is lowered dramatically mostly due to complex distortions occuring in applications, which are very different with that stimulated by computers. Utilizing images of the models as training samples, the network was reconstructed and retrained. Good results were obtained. And to approach image preprocessing problems, such as location and segmentation, an efficient method of quick target detection and location is proposed based on binary morphological erosion algorithm..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 20, Issue 7, 919 (2000)
Color Image Correlation Recognition with Incoherent Light
[in Chinese], and [in Chinese]
A method of recognition of color image under incoherent optical system is proposed. A color image is decomposed into three monochromatic images to be processed, then a realizable phase-only optical transfer function (OTF) is designed. The passband of this OTF is optimized to increase the signal to noise ratio (SNR) andA method of recognition of color image under incoherent optical system is proposed. A color image is decomposed into three monochromatic images to be processed, then a realizable phase-only optical transfer function (OTF) is designed. The passband of this OTF is optimized to increase the signal to noise ratio (SNR) and to yield a sharp correlation peak. This OTF can be synthesized by a couple of filters. The experimental results on color image recognition are presented..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 20, Issue 7, 925 (2000)
Discrete Cosine Transform Based Binary Joint Transform Correlator for Fingerprint Identification
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A new binary joint transform correlator algorithm is presented which uses the discrete cosine transform technique to process the joint transform power spectrum. This binary joint transform correlator can compare a target fingerprint with four reference fingerprints. Compared with other joint power spectrum processing mA new binary joint transform correlator algorithm is presented which uses the discrete cosine transform technique to process the joint transform power spectrum. This binary joint transform correlator can compare a target fingerprint with four reference fingerprints. Compared with other joint power spectrum processing method such as slide-window local median threshold method, the correlator using this technique has better performance in terms of output peak-to-noise ratio, peak intensity and discriminate rate. The result of optical-electrical hybrid experiment has shown that this technique can greatly improve the discrimination ability of multiple fingerprint identification system..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 20, Issue 7, 931 (2000)
Instrumentation, Measurement and Metrology
Theoretical Simulation of Transmission Grating Spectrograph Diffraction Imaging
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The partial coherent diffraction theory is applied to determine the diffraction characteristics of the transmission grating spectrograph(TGS).X-ray intensity distributions on the imaging plane of TGS are given in closed form for two types of sources.Imaging simulation of TGS for the source in black body model is also pThe partial coherent diffraction theory is applied to determine the diffraction characteristics of the transmission grating spectrograph(TGS).X-ray intensity distributions on the imaging plane of TGS are given in closed form for two types of sources.Imaging simulation of TGS for the source in black body model is also presented..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 20, Issue 7, 865 (2000)
Mathematical Model for Fiber-Optical Non-Symmetrical Fabry-Perot Interferometric Cavity
[in Chinese]
The mathematical mode for reflectance and transmission of the fiber-optical intrinsic unsymmetrical Fabry-Perot interferometer (IUFPI) is presented. The mathematical model for fiber-optical cavity longitudinal change of a low fineness IUFPI and intensity of the interferometric lignt is also presented. If r′1=t1t′1r2=r,The mathematical mode for reflectance and transmission of the fiber-optical intrinsic unsymmetrical Fabry-Perot interferometer (IUFPI) is presented. The mathematical model for fiber-optical cavity longitudinal change of a low fineness IUFPI and intensity of the interferometric lignt is also presented. If r′1=t1t′1r2=r, and t1t′1=1-r′21≈1, then the interference of reflections from fiber optical IUFPI can be approximately regarded as interference of two beams with equal amplitude. In the same time, the mathematical model for output of optical-electronic converter and the interference intensity of two beams with equal amplitude is discussed. All the mathematical models are the foundation of fiber-optical IUFPI applications..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 20, Issue 7, 873 (2000)
Novel Usage of a Flat-Field Grating Spectrograph
[in Chinese], [in Chinese], and [in Chinese]
A novel usage of the flat-field spectrograph with a variable line-spacing grating in 5 to 40 nm spectral range is presented. The spectrograph can be used for any source-grating distances but with a constant distance from the grating to the flat focal plane and is highly flexible and adaptable for XUV and soft X-ray speA novel usage of the flat-field spectrograph with a variable line-spacing grating in 5 to 40 nm spectral range is presented. The spectrograph can be used for any source-grating distances but with a constant distance from the grating to the flat focal plane and is highly flexible and adaptable for XUV and soft X-ray spectroscopy experiments with different laser plasma target chambers..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 20, Issue 7, 879 (2000)
Lasers and Laser Optics
Experimental Study of the Amplification of Femtosecond Laser Pulses in Fiber Amplifier
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The Experimental results of amplification of 1.531 μm femtosecond laser pulses using Er3+-doped fiber amplifier is reported. The femtosecond pulses generated by a self-starting additive pulses mode-locked Er3+ fiber laser with pulse duration of 410 fs injected into the Er3+-doped fiber amplifier (6 m, high doping conceThe Experimental results of amplification of 1.531 μm femtosecond laser pulses using Er3+-doped fiber amplifier is reported. The femtosecond pulses generated by a self-starting additive pulses mode-locked Er3+ fiber laser with pulse duration of 410 fs injected into the Er3+-doped fiber amplifier (6 m, high doping concentration Er3+-doped fiber), the maximum amplification gain of 55(17.4 dB) and 64.4(18.1 dB) and the maximum single pulse energy (peak power) of 0.384 nJ(752 W) and 0.452 nJ(1295 W) have been obtained with forward and backward pumping respectively. The shortest output pulses duration are 501 fs and 309 fs with forward and backward pumping respectively..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 20, Issue 7, 937 (2000)
Study of a Raman Free Electron Laser with Pseudospark Discharge Without Guide Field
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A Raman free electron laser(FEL) beam with a pseudospark discharge has been simulated numerically by nonlinear model. It proves that the Raman FEL can obtain high power without guide field.A Raman free electron laser(FEL) beam with a pseudospark discharge has been simulated numerically by nonlinear model. It proves that the Raman FEL can obtain high power without guide field..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 20, Issue 7, 942 (2000)
Kerr-Lens Mode-Locked Femtosecond Laser for Nd:Glass Laser Amplifier System
[in Chinese], [in Chinese], and [in Chinese]
A Kerr-lens mode-locked femtosecond Nd:LMA laser pumped by laser diode is discussed. Through calculation and theory analysis, a Kerr-lens mode-locked femto-second Nd:LMA laser operating at wavelength of 1054 nm is demonstrated by using additional Kerr medium (SF57) with the large nonlinear coefficient and optimal cavitA Kerr-lens mode-locked femtosecond Nd:LMA laser pumped by laser diode is discussed. Through calculation and theory analysis, a Kerr-lens mode-locked femto-second Nd:LMA laser operating at wavelength of 1054 nm is demonstrated by using additional Kerr medium (SF57) with the large nonlinear coefficient and optimal cavity design. The transform-limited pulses as short as 610 fs duration, corresponding to spectra width of 2.1 nm, were obtained in this experiment, and laser output power is 15 mW..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 20, Issue 7, 947 (2000)
Materials
Determination for Refractive-index Profile of Polymer Waveguide by Photobleaching
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
It was demonstrated in the photobleaching experiment that the shrinkage effect of polymer film, could be fitted approximately by an exponentially decaying function. After taking into account of the shrinkage effect, the index profile of the polymer waveguide determined by data simulation is a Fermi function with the heIt was demonstrated in the photobleaching experiment that the shrinkage effect of polymer film, could be fitted approximately by an exponentially decaying function. After taking into account of the shrinkage effect, the index profile of the polymer waveguide determined by data simulation is a Fermi function with the help of m-lines method and the exact transfer matrix theory..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 20, Issue 7, 991 (2000)
The Spectroscopic Characteristics of Ytterbium Borate Laser Glasses
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The absorption and fluorescent properties of Yb3+ borate glasses were measured. The integrated absorption cross section and stimulated emission cross section of Yb3+ borate glasses were calculated. The effects of B2O3 content, glass modifiers (Zno and BaO) and high valency cations (Ti4+, La3+, Ta5+ and Nb5+) on the intThe absorption and fluorescent properties of Yb3+ borate glasses were measured. The integrated absorption cross section and stimulated emission cross section of Yb3+ borate glasses were calculated. The effects of B2O3 content, glass modifiers (Zno and BaO) and high valency cations (Ti4+, La3+, Ta5+ and Nb5+) on the integrated absorption cross section and stimulated emission cross section of ytterbium borate glasses were studied. Two methods were used to evaluate the stimulated emission cross section of ytterbium borate glasses. It is found that the reciprocity method is more appropriate for calculating stimulated emission cross section of ytterbium laser glasses..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 20, Issue 7, 995 (2000)
Spectral Properties of Dye TMQ Doped Silica Film
[in Chinese], and [in Chinese]
The UV-emission-dye TMQ doped silica film and slab were prepared by the sol-gel process with the maximum concentrations of 1.24×10-2 mol/L and 1.5×10-3 mol/L respectively. Because of the binding effect of the “cage” and the polarity of the “cage” in the silica host, concentration quench of TMQ was not observeThe UV-emission-dye TMQ doped silica film and slab were prepared by the sol-gel process with the maximum concentrations of 1.24×10-2 mol/L and 1.5×10-3 mol/L respectively. Because of the binding effect of the “cage” and the polarity of the “cage” in the silica host, concentration quench of TMQ was not observed in the emission spectra and a 10 nm red shift was found, compared to that of TMQ-cyclohexane solution..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 20, Issue 7, 1000 (2000)
Optical Devices
A Dense-Wavelength-Division-Multiplexer by Using a Three Arm Mach-Zehnder Interferometer
[in Chinese], and [in Chinese]
A new type fiber interferometer has been fabricated. It is a Mach-Zehnder Interferometer made of two 3×3 single-mode fiber couplers connected by 3 single-mode fibers. The lengths of these 3 single-mode fiber are L, L+ΔL, and L+2ΔL respectively. This interferometer acts as a 3 channel wavelength-division-multiplexeA new type fiber interferometer has been fabricated. It is a Mach-Zehnder Interferometer made of two 3×3 single-mode fiber couplers connected by 3 single-mode fibers. The lengths of these 3 single-mode fiber are L, L+ΔL, and L+2ΔL respectively. This interferometer acts as a 3 channel wavelength-division-multiplexer. The wavelength between two channels is dependent on ΔL only. The experimental sample tested offers 1.6 nm wavelength division spacing and 0.6 dB total insertion loss at 1.5 μm working wavelength..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 20, Issue 7, 952 (2000)
Study of Arc-Type All-Optical Waveguide Switch Based on Self-Focusing Substrate
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The beam-propagation method (BPM) was used to analyse the structure of all-optical waveguide switch. The switching characteristics of all-optical waveguide switch based on self-focusing substrate are compared with that based on self-defocusing substrate. It is indicated that the all-optical switch based on self-focusinThe beam-propagation method (BPM) was used to analyse the structure of all-optical waveguide switch. The switching characteristics of all-optical waveguide switch based on self-focusing substrate are compared with that based on self-defocusing substrate. It is indicated that the all-optical switch based on self-focusing substrate shows many advantages such as low switching power and digital switching feature. The waveguide parameters were optimized by BPM..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 20, Issue 7, 957 (2000)
Simultaneously Realizing Multi-Wavelength Conversion Using Nonlinear Optical Loop Mirror
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Multi-wavelength conversion was simultaneously achieved by using nonlinear optical loop mirror (NOLM).The maximum separtion of the wavelength conversion between the control laser and the signal laser is larger than 25 nm. In the system, the gain switched distributed feed-back laser-diode is used as the control pulse wiMulti-wavelength conversion was simultaneously achieved by using nonlinear optical loop mirror (NOLM).The maximum separtion of the wavelength conversion between the control laser and the signal laser is larger than 25 nm. In the system, the gain switched distributed feed-back laser-diode is used as the control pulse with the pulse width of 20 ps, the spectrum-sliced fiber amplifier light source is used as the signal lasers with multi-wavelength output. The performance of the converted signal with different wavelength depends on the control optical power or the direction of the polarization controller in NOLM..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 20, Issue 7, 962 (2000)
Pupil Filters Improving Axial Resolution
[in Chinese], [in Chinese], and [in Chinese]
According to superresolution theorem of improving axial resolution, a new axial pupil filters are proposed. The pupil filters are neutral in the transverse direction and superresolving in the axial direction. The filters have small value of M, defined as the maximum value of sidelobes intensity relative to the central According to superresolution theorem of improving axial resolution, a new axial pupil filters are proposed. The pupil filters are neutral in the transverse direction and superresolving in the axial direction. The filters have small value of M, defined as the maximum value of sidelobes intensity relative to the central core, and relatively good effect of superresolution is attained. The new filters function based on these results are suggested and the superresolving function of midzone of the filters are discussed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 20, Issue 7, 968 (2000)
Retro-Reflective Properties of a Micro-Square-Prism
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The properties of the micro-square-prism array are studied theoretically. Its retro-reflective properties are demonstrated. By using the method of geometrical optics, the limit of the total reflection to the incidence and the influence of the available reflective area on the retro-reflectivity are studied. The effect oThe properties of the micro-square-prism array are studied theoretically. Its retro-reflective properties are demonstrated. By using the method of geometrical optics, the limit of the total reflection to the incidence and the influence of the available reflective area on the retro-reflectivity are studied. The effect of surface reflection of the array on retro-reflectivity is presented. For contrast, the properties of the micro-triangle-prism array is given as well. The result obtained is a theoretical foundation for designing and manufacturing the micro-square-prism retro-reflector..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 20, Issue 7, 973 (2000)
An Apodization Mask Based on Circle Grating Function with Different Space in Confocal Microscope
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The performance evaluation criterion based on polar coordinates is presented for the system with superresolving pupil mask. Then a mask based on circle grating function with different spacings and a math model are presented. The computation simulation results show that in confocal optic system this mask can change the The performance evaluation criterion based on polar coordinates is presented for the system with superresolving pupil mask. Then a mask based on circle grating function with different spacings and a math model are presented. The computation simulation results show that in confocal optic system this mask can change the point amplitude response. It can improve the resolution, while increase the image contrast..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 20, Issue 7, 979 (2000)
Multiple Kirchhoff Integral Method for Metal Blazed Gratings
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Supported by the boundary conditions of the scattering field related to the incident field through the Fresnel coefficients, and by the reciprocity theorem and the equivalent field principle, the multiple Kirchhoff integral method for metal blazed grating is developed. Under the conditions of Littrow mounting and fixedSupported by the boundary conditions of the scattering field related to the incident field through the Fresnel coefficients, and by the reciprocity theorem and the equivalent field principle, the multiple Kirchhoff integral method for metal blazed grating is developed. Under the conditions of Littrow mounting and fixed angular deviation mounting, illuminated by plane wave, the efficiency of ideal conductor blazed gratings is calculated. The stability and the self-consistency of this method are discussed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 20, Issue 7, 984 (2000)
Quantum Optics
Effects of the Motion of Atomic Mass Centre and Field Mode Structure on Dynamics of Field Phase
[in Chinese], and [in Chinese]
The effects of the motion of atomic mass centre and field mode structure on the dynamics of the field phase in the Jaynes-Cummings model are discussed by means of the Hermitian phase formulas of Pegg and Barnett. The time evolutions of the phase probability and the phase fluctuation, with the motion of atomic mass centThe effects of the motion of atomic mass centre and field mode structure on the dynamics of the field phase in the Jaynes-Cummings model are discussed by means of the Hermitian phase formulas of Pegg and Barnett. The time evolutions of the phase probability and the phase fluctuation, with the motion of atomic mass centre neglected and the motion not neglected, respectively, is derived. Under the two conditions, the dynamics of the field phase are compared. The results show that the motion of atomic mass centre leads to the periodic evolution of the dynamics of the field phase and this period depends on the field mode structure parameter..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 20, Issue 7, 890 (2000)
Rapid Communications
SHG Stability of Thermally Poled SiO2-GeO2 Films
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Sol-gel method was used to prepare SiO2-GeO2 films. The relative intensity of second-harmonic generation(SHG) signals of the thermally poled films and their relaxations were measured. By comparing the decay of second-harmonic generation of the films with different substrates and under different temperatures,it is shownSol-gel method was used to prepare SiO2-GeO2 films. The relative intensity of second-harmonic generation(SHG) signals of the thermally poled films and their relaxations were measured. By comparing the decay of second-harmonic generation of the films with different substrates and under different temperatures,it is shown than the stability of charge near the interface between the film and substrate is influenced by the bulk electric resistance of the substrate,and this charge character consequently influences the SHG stability of the film..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 20, Issue 7, 1004 (2000)
Spectroscopy
Study of the Photon-Echo by Polarization Beat Spectroscopy
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Photon echo in polarization beat spectroscopy is studied for a V-type three-level system. When the pump beams have broadband linewidth, one-photon four-wave mixing (FWM) is related to the three-pulse stimulated photon echo with relative time delay τ>0. The result coincides with the case when the beams have narrow liPhoton echo in polarization beat spectroscopy is studied for a V-type three-level system. When the pump beams have broadband linewidth, one-photon four-wave mixing (FWM) is related to the three-pulse stimulated photon echo with relative time delay τ>0. The result coincides with the case when the beams have narrow linewidth, τ<0. This technique can achieve Doppler-free precision in the measurement of the energy level splitting between two excited states..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 20, Issue 7, 896 (2000)
Time-Resolved Spectral Study of A3Π0 State of Molecule InCl
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The fluorescence spectroscopy of the A3Π0→X1Σ+ transition has been obtained and time-resolved spectra were measured by laser induced fluorescence. The collision-free fluorescence radiative lifetime of τ0≈370 ns is proposed for the A3Π0 and value for relaxation rate constant of kQ≈9.87×10-11 cm3*molec-1*s-1 is obtaThe fluorescence spectroscopy of the A3Π0→X1Σ+ transition has been obtained and time-resolved spectra were measured by laser induced fluorescence. The collision-free fluorescence radiative lifetime of τ0≈370 ns is proposed for the A3Π0 and value for relaxation rate constant of kQ≈9.87×10-11 cm3*molec-1*s-1 is obtained..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 20, Issue 7, 902 (2000)
Study of the Ba 6p3/2ns Autoionizing Rydberg States
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Using a multi-step laser excitation technique, the excitation spectra of the Ba 6p3/2ns (J=1) autoionizing states below the 6p1/2 limit are studied. The experimental data are compared with the results of an R-matrix calculation combined with multichannel quantum defect theory (MQDT). The agreement between experiment anUsing a multi-step laser excitation technique, the excitation spectra of the Ba 6p3/2ns (J=1) autoionizing states below the 6p1/2 limit are studied. The experimental data are compared with the results of an R-matrix calculation combined with multichannel quantum defect theory (MQDT). The agreement between experiment and theory is satisfactory..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 20, Issue 7, 908 (2000)
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