The principle of the subnatural linewidth two-photon spectroscopy is described in this paper. The optimum conditions for observing the subnatural linewidth are analyzed. The expression of two-photon absorption probability for the decaying optical pulse series excitation is given and a simple experimental method is suggested.

This paper reports the experimental results on the frequency doubling characteristics of Mg:LiNbO3 crystals (phase matching, photorefractive effect), and the parametric optimization for intracavity frequency doubling. Using Mg:LiNbO3 for intracavity frequency doubling of an acousto-optic Q-switched (3KHz) Nd:YAG laser (3.6 kW, pumping power), output of green light with an average power of 2W, pulse width of 300 ns, peak power of 2.3 kW and conversion efficiency of 34% at 0.53μm have been obtained.

The small signal gain and saturation intensity of an X-ray preionized avalanche discharge XeCl laser are determined with the maximam loss method over a gas pressure range of 2 to 5 atm., and they are found to increase with the laser gas pressure up to at least 5 atm.

In this paper two-pass SHG by a LiNbO3:MgO crystal placed in the resonator of a Q-switched YAG laser is studied and the conversion efficiency of about 60% has been obtained.

The polarization characteristics of the laser with a LiF:F2- Q-switch are studied. The reasons causing the polarization are presented.

The conversion efficiency and tuning range excited with nitrogen laser or Nd:YAG (THG 354.7nm) laser have been measured. It was found that these dyes give higher conversion efficiency than PPO and eoumarin -120. The tuning range is between 4075-4300A.

A CO2 laser producing lines of (00°2- [10°1, 02°1]I,Ⅱ) transitions is described. This laser is a conventional selective branch CO2 laser with intracavity hot cell. The technique can double the number of output lines of CO2 lasers. The experimental results are given.

The experimental observation and theoretical analysis on the Raman-resonant four-wave parametric mixing process in rubidium vapour have been made. The theory agrees with the experimental results.

This paper reports a new method to compensate the wavef ront distortion. Taking a laser beam of astigmatic aberration as an example, the state of the laser beam compensating system can be given by the axial hologram of the laser beam. And the techniques of double-slit filter and "cross-filter" can be used to extract the near field wavef ront of the laser beam with phase modulation and amplitude fluctuation. It is possible to use the active compensating technique of laser beam in a high power Nd-glass laser system.

In this paper, we propose a principle and a method of rising the accuracy for the Talbot shearing interferometer. Tests for prisms, lenses and phase objects are given and their filtering shearing interferometric images of the respective diffraction order are also presented. Finally, the experimental results that coincide with the theory are given.

Measurement of the refractive index profile of the Ti-diffused LiNbO3 planewaveguides was performed. The measurement principle and the preparation of samples are briefly described and the results are given.

On the glass waveguide formed by ion exchange, a silver metal layer is deposited, thereby the graded refractive index waveguide with metal-cladding is made. Eigenvalues are solved by ray-optics method. Experimental results show that the measured values of effective, refractive indices agree with the theoretical ones.

The experimental studies on the propagation characteristics of modes in the photoresist-glass planar optical waveguides are reported. The effects of the photoresist film overlays on the propagation of modes in glass planar optical waveguides by silver-ion exchange are measured. The experiments of the strip-loaded curved waveguides are described.

We have constructed a long life time multi-point contact MIM. The diode mount is adjusted by combining the mechanical and electrical structure. Using W-Ni, W-Fe and W-Cu multi-point contact MIM, the fast response signals at 23 GHz in em wave, 50 GHz in mm wave, 10.6μm in CO2 laser and 6328 A in He-Ne laser have been detected. The beat signal of about 30 MHz have been observed from two grating-tuned CO2 lasers.

An optical switch with an all avalanche transistor driver is developed. It is designed to reliably select a single pulse from a mode-locked pulse train. Its operational principle and experimental results are described. The test indicates that this device has the advanteges of stable performances, reliable operation, short delay time(-20 ns), minimum jitter, long life time and no electromagnetic disturbances.

A new circuit for repetitive pulsed supply is presented in this paper. It has the advantages of high reliability, high repetition accuracy of output voltage (typically up to 10-8), stable frequency, simple circuit structure and easy adjustment and maintenance. In addition, when the fiashlamp is continuously conducted, the flashlamps, silicon controlled rectifiers, rectifying diodes and other circuit elements would not be damaged.

In this paper, we report several changes observed after 7402 cells were irradiated with a CW argon laser of low intensity. The effects on 7402 cells treated and untreated with HPD after being irradiated are compared. The wavelength effect is studied simultaneously.

The structure and performances of a small CW HF chemical laser are described. A total of 18 lines from V=1-0 and 2-1 transitions have been observed. The maximum single line output is 900 mW. In single frequency operation, the short-term frequency stability is about 20-30 MHz.

We have demonstrated experimentally that the photodiode array is a useful tool for realtime measurement of two dimensional farfield pattern for semiconductor lasers thereby one can obtain the transverse mode structure which appears very important in optic fiber communication.

Safisfactory clinical results of 48 cases on sequels of celebral concussion treated with low power (7mw) He-Ne laser aeupoint irradiation in the past three years are reported. Through follow up, 27 cases (60%) were healed completely, 17 cases (36%) improved, 2 eases (4%) unchanged. The total effective rate reaches up to 96%.