Acta Optica Sinica
Co-Editors-in-Chief
Qihuang Gong
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]

The finiteness of diffractive order of the phase grating and the relations between the diffractive orders and the incident angle are discussed by means of the vector diffraction theory. The results are in correspondence with that attained by the optical path method. The distribuion of each diffractive order is illustrated at different incident angles and the diffractive direction of each diffraction wave are given. It is pointed out that while there only exist the zero-order reflection wave and the zero-order transmit in free space layer, the diffraction waves of higher diffractive orders may exist in the substrate layer.

Jan. 01, 1900
  • Vol. 18 Issue 7 870 (1998)
  • [in Chinese], [in Chinese], and [in Chinese]

    In the phase shifting microscopic interferometry profiler, surface profile distortion exists due to the limitation of finite spatial bandwidth of the microscopic system. The phenomenon through simulation computation was analyzed. A suggestion to improve the response of the system was given.

    Jan. 01, 1900
  • Vol. 18 Issue 7 877 (1998)
  • [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]

    We investigate the relative diffraction efficiency of a volume hologram where a spherical wave is used as the reference beam. Through theoretical analysis we find that the cross-talk performance of a volume hologram with a spherical reference wave is somewhat better than that with a planar reference wave. This phenomenon is explained and demonstrated. After comparing the readout images by a spherical reference wave with those by a planar reference wave, we also verify that a spherical reference wave is of little effects on the readout image quality. These features imply not so rigorous requirements on the parallelism of the reference beam in a volume holographic memory. In addition, a phenomenal analytical expression to approximately calculate the relative diffraction efficiency of a volume hologram with a spherical reference beam is presented.

    Jan. 01, 1900
  • Vol. 18 Issue 7 906 (1998)
  • [in Chinese], [in Chinese], and [in Chinese]

    A new phase unwrapping algorithm is presented. It is mainly used in the cases of optical smooth surface with few low modulation and speckle points, no heavy noise. The algorithm is based on Zernike polynomials. It fits the data into Zernike polynomials and filters the unreasonable data through a threshold. The new algorithm shows high speed calculation.

    Jan. 01, 1900
  • Vol. 18 Issue 7 912 (1998)
  • [in Chinese], [in Chinese], and [in Chinese]

    A novel mthod to compress laser pulsewidth by coherent wave mixing in silicon is proposed. Calculation shows that the pulsewidth of the compressed and amplified signal beam approaches 70% of that of the input beam for nanosecond and picosecond laser pulse within the damage threshold of material. Influence of parameters such as pump beam intensity and wave mixing angle on the compressed pulsewidth of signal beam was discussed.

    Jan. 01, 1900
  • Vol. 18 Issue 7 918 (1998)
  • [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]

    A remote measurement system of solid surface displacement by laser Doppler effect of grating which was used to produce beat frequency is discussed. An acousto-optical system could be conveniently adjusted. The displacement measurement at the remote distance of 50 meters was realized.

    Jan. 01, 1900
  • Vol. 18 Issue 7 923 (1998)
  • [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]

    The testing method for imaging quality of visible light systems has been applied in infrared optical systems. A device for testing the imaging quality of infrared optical systems has been developed. With the control of 486DX2/66 computer, the device can implement data acquiring, storing and processing of images produced by an infrared optical system. The imaging pictures in different colors or gray levels can be shown on the display screen. It can also test the energy distribution of imaging pictures of various infrared optical systems.

    Jan. 01, 1900
  • Vol. 18 Issue 7 928 (1998)
  • [in Chinese], [in Chinese], [in Chinese], and [in Chinese]

    A two-mode ring gain-noise laser model taking account of full saturation effects with multiplicative noise induced by gain fluctuations is concerned. An exact analytical expression for laser intensity distribution is obtained on resonance with equal mode pump parameters. It is found, through a comparison with the currently used models where multiplicative noise arises from loss fluctuations, that the occurrence of nonlinear multiplicative noise coefficient weakens the anomalous characteristics brought about to the laser intensity statistical properties by introducing multiplicative noise, and this kind of weakening is more apparent for larger multiplicative noise or smaller laser loss.

    Jan. 01, 1900
  • Vol. 18 Issue 7 856 (1998)
  • [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]

    Over 1 W of CW TEM00 green output from LD end-pumped Nd:YVO4 with LBO intracavity-doubled all-solid-state laser was demonstrated. The maximum CW TEM00 output of 1.2 W at 532 nm was obtained by using I-type noncritical phase-matched (NCPM) temperature tuning of LBO at the pumping power of 5.5 W. The optical-optical coversion efficiency of the all-solid-state laser is 22%, the electrical-optical coversion efficiency is 3%.

    Jan. 01, 1900
  • Vol. 18 Issue 7 862 (1998)
  • [in Chinese], [in Chinese], and [in Chinese]

    A flashlamp-pumped Ti:Al2O3 laser with double simmer currents is studied. A technique of double simmer currents is used and the influence caused by strong simmer current on the laser output energy is discussed. We find that laser efficiency increases when strong simmer current enhanced. The appropriate simmer current is 1.6 A. Laser energy more than 600 mJ and overall efficiency 0.16% are obtained.

    Jan. 01, 1900
  • Vol. 18 Issue 7 866 (1998)
  • [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]

    The gold double-disk targets were irradiated by 3ω0 laser, and time-space properties of X-ray spectra were investigated at “Xingguang” laser facility. A four-pinhole transmission grating array and a picosecond frame camera were combined, and the three-dimensional measurement of X-ray time, space and energy spectra was conducted on the laser shotting region and X-ray radiation ablating region. The X-ray relaxation process and some important physics results such as the N band, O band and 0th spectra versus time and space as well as two-dimensional spatial distribution of plasma jet and plasma expansion speed were observed.

    Jan. 01, 1900
  • Vol. 18 Issue 7 890 (1998)
  • [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]

    The laser-driven ablation parameters are measured by using the method of time-integrated and time-resolved crystal spectrometers. The following experimental results are obtained. For aluminium target driven by 0.35 μm laser with absorbed laser intensity of 1.4×1014 W/cm2, mass ablation rate measured by time-integrated crystal spectrometer, is 6.8×105 (g/cm2·s), and ablative pressure is estimated to be 4.7×1012 Pa and 4.4×1012 Pa according to momentum conservation and energy conservation, respectively. Mass ablation rate with absorbed laser intensity of 1.6×1014 W/cm2, measured by time-resolved crystal spectrometer, is 6.1×105 (g/cm2·s) and ablative pressure is estimated to be 4.4×1012 Pa from energy conservation. These results are in accordance with the results obtained by other laboratories within the experimental error.

    Jan. 01, 1900
  • Vol. 18 Issue 7 895 (1998)
  • [in Chinese], [in Chinese], [in Chinese], and [in Chinese]

    The observations on the stimulated photorefractive scattering self-pumped phase conjugator (SPS-SPPC) in Ce-doped BaTiO3 demonstrate that the self-built pumped paths in the SPS-SPPC are induced by the scattering seeds. Using these results, a formation mechanism of the SPS-SPCC is presented, which is related to the scattering seeds, contradirectional two-wave mixing and four-wave mixing. The production conditions and characteristices of the pumped paths are given. It shows that the large backscattering coefficient is always advantageous to the production of these paths. The maximum of the phase conjugition reflectivity attains 80%.

    Jan. 01, 1900
  • Vol. 18 Issue 7 840 (1998)
  • [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]

    Stimulated Brillouin scattering (SBS) phase-conjugate mirror was used to produce XeCl laser beam of good optical quality and short time duration. The amplified phase-conjugate beam duration could vary from 50 ns to 17 ns, by changing the pump pulse energy or the depth of the lens focus into the SBS medium. The spatial quality of this beam was improved.

    Jan. 01, 1900
  • Vol. 18 Issue 7 845 (1998)
  • [in Chinese], and [in Chinese]

    High-order optical harmonic emission from a single atom exposed in the intense chirped laser pulses has been calculated. Harmonic spectral shifting and broadening are found. Namely, for the negatively chirped pulses, blue-shifting can be observed in the front part (11 st~51 st order) of the harmonic plateau. But the back part from 53rd to 91st harmonic orders occur to red-shift. When the sign of chirp is changed to be positive, the spectral shifting is just reverse. Regardless the sign of chirp every harmonic order is broadened in different degree for different order number. The bandwidths of individual peaks are broad enough to support subfemtosecond pulses if the pertinent phase conditions can be met. These calculation results agree well with the recent experiment performed by Zhou et al. although the opposite spectral shifting in the back part of harmonic plateau is not reported in their experiment. It indicates that a tunable, ultrashort soft X-ray source can be obtained by controlling the degree and sign of chirp.

    Jan. 01, 1900
  • Vol. 18 Issue 7 851 (1998)
  • [in Chinese], [in Chinese], [in Chinese], and [in Chinese]

    In active fiber two kinds of nonlinearity, nonlinear polarization and gain saturation, laed to the frequency spectrum broadening of optical signal. Gain saturation distorts its envelope, and affects the self-phase-modulation (SPM) caused by nonlinear polarization. It can be expressed by a transmission function f(z). A formula of f(z) with a power series derived from NLS equation is given, and the frequency broad band can be estimated by B=2F(1+μ). Because of f(z)>>1 in the active fiber, the broadening can be compared with initial band of optical signal in the optical communication system having many optical fiber amplifiers with high gain and high output power.

    Jan. 01, 1900
  • Vol. 18 Issue 7 883 (1998)
  • [in Chinese], [in Chinese], [in Chinese], and [in Chinese]

    A self-correcting method to calibrate the error of phase shifter is presented. Firstly, the fast Fourier transform (FFT) was used to anlayze the carrier frequency fringes, the characteristic curve of phase shifter was obtained from a series of carrier interferograms by FFT. Using this curve, then the phase shifter was corrected by an iterative self-correcting process relying on the interferometer. The self-correcting experiment with IR interferometer shown that the nonlinearity of phase shifter was reduced from 5% to 0.2%.

    Jan. 01, 1900
  • Vol. 18 Issue 7 932 (1998)
  • [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]

    Light-emitting diodes based on ROPPV-12/Alq3 heterojunction were fabricated, in which ROPPV-12 [poly(2, 5-Didodecyloxy-1, 4-Phenylenevinylene)] was a hole type semiconducting polymer, and 8-hydroxyquinoline aluminum (Alq3) was an electron type semiconducting low mass organic material. The emission spectrum of the device based on heterojunction ROPPV-12 (70 nm)/Alq3 (20 nm) is similar to that of POPPV-12′s single layer device. The emission spectrum of the device based on heterojunction ROPPV-12 (70 nm)/Alq3 (32 nm) is composed of two parts, one is originated from ROPPV-12, the other is from Alq3. The emission from ROPPV-12 is the main emission at low drive voltage. While with the increase of drive voltage, the emission from Alq3 becomes the main emission gradually. In other words, the electroluminescence of the later device is color voltage-dependent. The brightness, current and luminescent efficiency of the former device is much better than the later device. The emission mechanism is presented.

    Jan. 01, 1900
  • Vol. 18 Issue 7 938 (1998)
  • [in Chinese], [in Chinese], [in Chinese], and [in Chinese]

    The results of numerical analysis show that the uniformity of illumination of laser fusion target can be improved by using a random phase plate (RPP), though the magnitude and phase of laser beams irradiating the target plane are practically fluctuated. Any random phase distribution of the random phase plate has less effects on the unformity of laser irradiation on the target plane. Besides, the intensity distributions of the target plane defocused are discussed.

    Jan. 01, 1900
  • Vol. 18 Issue 7 943 (1998)
  • [in Chinese], and [in Chinese]

    An improved method for the design of pseudorandom encoding of phase-only filters is presented, The fully complex modulation is pseudorandom encoded to the bi-amplitude phase modulators. The performances of the newly designed filter are greatly improved compared with that of minimum Euclidean distance optimal filter (MEDOF).

    Jan. 01, 1900
  • Vol. 18 Issue 7 950 (1998)
  • [in Chinese], and [in Chinese]

    Modulation instability (MI) and consequent signal-to-noise-ratio (SNR) degradation in optical fiber transmission system with cascaded optical amplifiers are analyzed. Expressions for evaluating MI gain and SNR are derived. For a long distance transmission system, MI may degrade SNR significantly even at relatively low signal power.

    Jan. 01, 1900
  • Vol. 18 Issue 7 881 (1998)
  • [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]

    By the local mode-coupled theory, transmission properties of two kinds of fiber probes, the etched taper and the pulled taper, which are used for scanning near-field optical microscopy, have been analyzed and compared. The coupling efficiency distribution along the probe taper and the transmission efficiencies versus the taper length, the tip diameter and the wavelength are given.

    Jan. 01, 1900
  • Vol. 18 Issue 7 886 (1998)
  • [in Chinese], [in Chinese], [in Chinese], and [in Chinese]

    Cavity length shift is the main reason that causes the instability of an actively mode-locked fiber ring laser. We derived the relation between the phase noise of output pulses and the cavity length shift. By suppressing the phase noise, we made the actively mode-locked fiber ring laser operation stably for more than 8 hours.

    Jan. 01, 1900
  • Vol. 18 Issue 7 956 (1998)
  • [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]

    Jan. 01, 1900
  • Vol. 18 Issue 7 960 (1998)
  • [in Chinese], and [in Chinese]

    The 4s-4p transitions for the Cu-like isoelectronic sequence from In(z=49) to U(z=92) have been calculated by using the relativistic multiconfiguration Dirac-Fock method. The results obtained are in good agreement with the experimental data avaiable. This is verified the importance of quantum electrodynamics (QED) corrections in these highly stripped ions.

    Jan. 01, 1900
  • Vol. 18 Issue 7 901 (1998)
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