In this paper, the image processing method of flow field interferograms containing shock wave has been investigated. The method includes an algorithm of rapid fringes thinning, an algorithm of extracting shock wave-fronts and an algorithm of registering time-serial shock wave- fronts. An application software based on these algorithms is developed for use with the PC-VISION 100 image processing system. The experimental results show that this method can be used to calculate the propagation velocity and pressure distribution of shock wave-fronts and the functions of flow field interferogram are increased.

We report on the temporal characteristics of output pulses of a gain-switched Ti3+:A12O3 laser pumped by a frequency-doubled Q-switched Nd:YAG laser. The minimum laser pulsewidth of 1.2 ns has been observed. The pulsewidth can be varied from 5 ns to 27.5 ns continuously under certain experimental conditions. Using only one output coupler the tuning range of the laser was from 730 nm to 850 nm. The maximum output pulse energy of 4.7 mJ and the spectral content of 0.13 nm (FWHM) at 780 nm prisms were obtained, by using three intracavity prisms.

The SHG from a colliding pulse mode-locked (CPM) unstable resonator Nd:YAG laser with a antiresonant ring structure is obtained by using intracavity frequency doubling of BBO crystal. The SHG energy conversion effiency of 50. 4% is measured . We demonstrate theoretically and experimentally that the conversion efficiency of intracavity frequency doubling is higher than that of extracavity one in this kind of laser using BBO crystal.

The electron beam and radiation synchronization in the cavity of a free electron laser has been investigated. This is important to the design of a laser cavity. The effect of Brewster window inside a cavity on the radiation trajectory is discussed in this paper. A fine adjustment device driven by a personal computer is developed, the cavity axis can be moved by the device in the range of ±30 mm with a resolution of 1 μm.

The structural characteristics of ATCC, ATCB and ATMC crystals are studied. For the first time, this paper reports the nonlinear optical coefficients and SHG properties of ATCB and ATMC crystals. Comparisons have been made among the nonlinear optical properties of ATCC, ATCB and ATMC crystals. The difference of the properties in these three crystals is analysed and the dependence of properties on sturctures is discussed.

The photorefractive grating in a KTa1-xNbxO3:Cu (x=0.32) crystal was erased with an expanded beam and one of the writing beams, respectively. Through the different erasing effects, it was further demostrated that besides a periodic space-charge field a DC space-charge field was formed simultaneously during writing. Meanwhile the dynamics of erasing a DC space-charge field was also studied. In addition, by irradiating KTa1-xNbxO3:Cu crystal with one of the writing beams under an applied electric field before writing, the influence of the formation of DC space-charge field on the diffraction intensity was investigated.

A new phenomenon in the medium consisting of multi-level atoms is revealed, which states that a large index of refraction is achievable for a resonant light with the help of atomic coherence.

The efficient infrared-upconversion luminescence generation, which was considered as an enhanced third-order nonlinear optical process by our primary study, was used as a probe of the bulk symmetry properties and mechanism of light-emitting porous silicon layer (PSL). It was found that the crystalline anisotropy of crystal silicon is almost remained for PSL. The observation of laser-induced decreasing of infrared-upconversion signal demonstrated that the presence of hydrogen in the PSL, is essential to the luminescence efficency.

The confirmation of energy transfer from TTPP to Pc in binary molecules of TTPP-O-Pc and TTPP-O-(CH2)5-O-PC has been made by studying the luminescence and excitation spectra, and the two emission bands in the latter were distinguished. The nondegenerate four-wave mixing (NDFWM) was employed to investigate the relaxation processes of excited states (τ1) and charge transfer (τ2). The relaxation times of τ1 and τ2 were, for the first time, obtained to be 4.5 ps and 18.5 ps for TTPP-O-Pc, and 4.2 ps and 82 ps for TTPP-O-(CH2)5-O-Pc.

The Jones matrix method analysis of Raman induced Kerr effect spectroscopy (RIKES) is presented. The intensity of weak linear polarized monochromatic probe beam is not only dependent on the Jones matrix of each optical device in pump- probe technique, but also dependent on the Jones matrix of nonlinear medium sample, in which an intensity dependent dichromism and birefringence are induced by a strong circularly polarized pump beam. Take account of the disadvantage factors of the additional static birefringe in the sample and other optics, which will produce a background intensity in the polarized signal. The complete expression of power transfer function and the annihilation condition of RIKES are derived. The PIKES experimental results of the toluene (C7H8) are given briefly.

The transmissive effect in BaTiO3 crystal self-pumped phase conjugators was studied from the dependence of the emergent angle of the transmitted phase conjugate beam on the incident angle of the pumping beam, the light path of the transmited phase conjugate beam in a BaTiO3 crystal, and its transmissivity versus the angle between the pumping beam and c axis of a crystal. It was found that there indeed exists a transmitted phase conjugate beam in the self- pumped phase conjugation of a BaTiO3 crystal and the transmitted beam is separated from the self-pumped phase conjugate beam by an internal reflection of the crystal surface.

The phase dynamical and statistical properties of the field in the intensity-dependent coupling J-C model are studied by using the Pegg-Barnett phase theory. Under certain conditions, the phase locking and squeezing are behaved, and the number- phase uncertainty product becomes the minimum for a coherent state.

We report in this paper the measurement results of the relative intensity noise (RIN) in GaAs-AlGaAs laser arrays and the comparison with that of single stripe lasers. The results are in agreement with the noise theory based on the rate equation. The experimental measurements include relative intensity noise versus drive current, modulation frequency and temperature. And in these circumstances the theoretical prediction that the maximum of the relative intensity noise occurs when the lasers run exactly at their threshold current level is examined.

The polycrystal thin films of the diluted magnetic semiconductors Zn1-xFexSe were prepared by vacuum evaporation. The structure and composition of the films were examined by X-ray diffraction and scanning electron microscopy. Optical absorption data showed that the energy gap E 8 decreases linearly with the composition x of Fe2+ ions. The best fitted relation is Eg=2.722-2.224x.

The basic principle of weak absorption measurements performed with photothermal deflection technique is discribed. An experimental setup with multiple pumping lasers has been constructed, the testing procedure and the results of a simple measurement example are presented.

Taking into account of the fourth- order nonlinear refractive index, we have obtained the soliton solution of the nonlinear equation which governs the propagation of optical pulse in group velocity dispersion (GVP) single-mode fibers. And we point out that there is a intensity threshold for the sech-type pulse compression.

The symmetry of the rotation-vibration spectra for triatomic molecules are described by means of the group U(5). The transition matrix elements of Raman scattering are calculated by using the group theory approach. The cross sections of vibrational and rotational Raman scattering are given. The results are in good agreement with the experimental values.

Using the linearized langevin equations and the spectral matrix, we discuss the fluctuation spectra of signal mode in the output field from a F-P cavity below or above threshold for the process of non-degenerate parametric down-conversion. It is indicated that the signal and idler modes usually are in minimum-uncertainty states.

In this paper the theoretical model and tunable feature Rb- Faraday anomalous dispesion optic filter (Rb-FADOF) in strong magnetic fields are discussed. Theoretical analyses and experimental obsarvations are in good agreement. The tuning capabilities of Rb-FADOF by changing the magnetic field have been obtained and some important practical results are also available.

A new experiment was carried out on a modern HP-workstation with a 19" color screen under usual office lighting conditon. In the middle of the screen two adjacent fields of differnet colors were displayed, either 2° or 10° in size. Both of the fields were fixed to the same CIELUV color difference in relation to the background of the screen at 5, 20, 50 and 80 CIELUV units respectively. The task of the observer was to evaluate these adjustments-perceived color difference of the left field is bigger than, same as, or smaller than that of the right field. The result shows that equal CIELUV color differences on displays lead to quite different subjective ratings. In particular, chroma in CIELUV system is very much overstimated.