The experimetal observation of optical damage of channel waveguides on LiNbO3 substrate by CCD is reported. We found that optical damage was propagation direction dependent.The optical damage can be partly erased by heating the sample. The resistance against optical damage of MgO doped LiNbO3, i.e. MgO:LiNbO3, is strongerthan that of pure LiNbO3.

Having both functions of beam splitting and focussing a home designed binary-optical beam splitter combined with a two-dimensional Dammann grating and a Fresnel zone plate is reported. This element is achieved by means of amorphous silicon nitride thin films. The split arrays are 3×3 and the focus length is 18 cm. The relative distribution error of the split beam intensity is less than 5%.

Monolithic integrated glass waveguide device consists of three parts, two spheroidal geodesic lenses and an etched out waveguide grating. The waveguide was formed by K+/Na+ exchanging method.The device was measured with a semiconductor laser, and the optical signal received by CCD was displayed on an oscilloscope. The Bragg diffraction with an efficiency of 30 percent was observed experimentally.

The core-cladding waveguide structure of a lithium niobate single crystal fiber with step refractive index profile is achieved by Mg-ion indiffusion processing. Characteristic equation and cut-off condition of the cladded crystal fiber are given, and some transmission characteristics of modes are discussed.

This paper describes the successful use of a coherent optical feedback system in realizing restoration of a degraded image. The experimental result shows the future prospects of the coherent optical feedback technique in image restoration.

This paper introduces a new method of real-time optical image subtraction realizedby grating encoding. In this method, two images are encoded by a one dimensional transmission-reflection grating, while decoding is completed by Fourier filtering. Thus, amplitude subtraction of the two images will be real-time resulted in the output plane of the optical system. The principle analysis for the method and experimental result are given. Finally, a brief discussion is made.

A pulsed Ti:sapphire laser tuning by a dispersion-Brewster beam-expanding prism is investigated. The coversion efficiency can be improved ～8% by feedback of the pump laser. The established tunable Ti:sapphire laser features a high laser output energy of 23 mJ/pulse,a high laser conversion efficiecy of up to 19%,and a linewidth of less than 0.01 nm.

An Erbium-doped-fiber ring laser, pumped with a 980 nm semiconductor laser, has successfully operated at the wavelength of 1.56 μm. The threshold pumping power of the laser is 5.2 mW. The laser has an excellent output property.

The first result in China of the generation of ultracold neutral metal clusters by laser vaporization/molecular beam techniques in the preliminary stage of our experiments is reported. The generated Aln clusters (n=2,…,6,7) are photoionized by excimer laser at 193 urn and detected with a TOF mass spectrometer. Meanwhile, remarks on cluster beam source of this kind and comparison of it with other different sources are briefly presented.

Combined with a DV-Xa calculation, the formation and stability of SixN±y cluster ions produced by laser ablation technique were investigated.It was observed in the mass spectrum that larger cluster ions were composed of one of the basic units,SiN3or SiN,,and other stable cluster ions.The mass spectrum shows that the maxima correspond to these cluster ions whose masses are times of the atomic mass of Si. The odd-even variation related to the number of N atom is believed to be caused by the differences of intensity of the intensity of the basic units.

Based on quantum theory of light, the noise power density spectrum and its time-spectrum formula of the intensity fluctuation of a two-mode laser are derived. Quantum statistical properties of a two-mode laser and its time-spectrum characteristics as well as the frequency tuning features of the frequency beat noise are analyzed and discussed. The study shows that the time-spectrum characteristics of the frequency beat noise of a two-mode laser can be applied to the frequency and power stabilization of two-mode laser can be applied to the frequency and power stabilization of two-mode lasers.

We have investigated Raman beam combination to improve the beam quality of a XeCl excimer laser. It was verified theoretically that the near diffraction-limited Stokes light could be obtained with abberated pump beams. The selection of Raman gas media was then discussed on steady and transient pump pulse conditions. Experimentally, we studied the Raman combining in H2 with two pump beams.The near diffraction-limited Stokes light was amplified intensely with unchanged far field distribution,resulting in a brightness increase of 3000 times. Finally we discussed the amplified spontaneous emission in a Raman amplifier.

In this paper we have proposed and studied the following 3 basic problems in beam propagation: 1) defination of beam quality and its measurements; 2) arbitrary beam propagation through real optical systems and 3) nonlinear propagation of real laser beams. Here, we are interested in the methods to solve these problems. We have analytically investigated the beam quality by assuming the phase aberrations as Gaussian random variables.For the nonlinear harmonic conversion of real laser beams, we have developed a theory by applying the spatial spectrum analysis to the nonlinear coupling.