The phase conditions for free electron lasers are analyzed on the basis of energy equations and Lorentz equations for the interaction of relativistic electrons with magnetostatic field and laser field. It is shown that the energy of relativistic electrons are reduced when the initial phase of incident light lies in the first and the fourth quadrants with respect to the relativistic electron heam. When the initial phase lies in the second and the third quadrants, the relativistic electrons are further accelerated.

In this paper, the eomputative formulae used to measure 2-D vibrational displacement and stress in the time-averaged method are derived. By combining the finite element method, the computation for the first-order bending vibration of a blade has been made, and the computable displacement is compared with that, measured directly by an eddying sensor. Holograms with as many as forty orders of fringes can be clearly observed, thus expanding the measurable scope of amplitude from 3λ to 10λ.

Experimental study on the stability of F2+ centers in oxygen doped LiF crystals is reported. The mechanism on the decay and stabilization by O of F2+ centres are discussed in detail. Experiments show that the decay process of F2+ centers in LiF is a second order reaction. The measurements of rate constants and activation energy of F2+ center decay in the range of room temperature indicate that the activation energy increases by about 0.2 eV and the rate constants decrease appreciably in oxygen doped LiF compared with the undoped crystals. A theoretical estimation of the difference of binding energy and that of electron affinity of F2+ centers between doped and undoped LiF crystals is also given briefly.

The experimental results of a long pulse width Nd-doped glass rod laser amplifier using a moving input laser beam are reported. The damage threshold for the amplifier increases by a factor of over 2 using laser light of 5-10 ms in duration, and the brightness of the amplified output beam increases obviously in comparison with that of the unmoving ones.

A method is described for semiconductor Si doping of organic colloidal dopants. Both P-type and N-type crystalline Si have been doped using arsenic, phosphor and boron. The electrical and opto-electrical characteristics of the doping area are investigated.

UV laser emission from the dye solutions of P-terphenyl in methanol, ethanol, cyelohexane and P-dioxane pumped by an UV-preionized KrF excimer laser is reported. Laser conversion effieiency is 21% when ethanol is used as solvent. UV tunable laser emission has been obtained in the range of 335.8-345.9 nm with the tuned linewidth of-8A.

A tunable LiF:F2 color center laser using 0.53μm laser as the pumping source is reported. In this experiment, the concentration of F2 center in crystal is about 6.2×1017 cm-3, a value higher than that previously reported. The linewidth of the tunable laser output around 0.69μm is 1.5 A with an energy conversion efficiency of 2.9%. There were no bleaching effects in crystal until 6000 pulses have been shot.

An electrically initiated HF laser of 1J output energy is reported. The influence of the operation parameters on the laser output characteristics are investigated experimentally.

A CW tunable CO laser operating at two wavelengths is reported and the output characteristics for line composition are studied.

Measurements of expansion coefficients (β) and refractive indexes (nD) and its gradienets (dnD/dt) are described. β, nD and dnD/dt of system POCl3-ZrCl4-Nd (CF3COO)3 are determined and dnD/dt is calculated by means of Gladstone-Dale equation. Elffect ofs 8 additives such as SeCl4 etc. on dnD/dt are studied.

A passively mode-locked YAG: Nd laser is used to study the damage in KC1, NaCl and KBr single crystals by picosecond pulse irradiation. Intrinsic breakdown threshold and self-focusing parameters are measured experimentally. The influence of intrinsic factors, such as self-focusing, inclusion and pulse width on the damage measurement are analysed.

An improved experimental setup for measuring picosecond absorption recovery time is reported. Absorption recovery time for cryptocyanine in ethanol is measured to be 16±3ps. Based on simplified two-level model the relaxation time for upper level of the cryptocyainie molecule is estimated to be 21*4ps.

Test on YAG: Nd rods of different qualities at low, moderate and CW energy pumping have been made. It is shown that compared to moderate energy pumping, the influence of crystal quality on laser output performances are more obvious.

A liquid crystal is used as polarized modulator to change the polarizability of optical wave and form the partially polarized laser speckle pattern and the statistical properties of the intensity of partially polarized laser speckle pattern are studied.

This paper discusses the dependence of the absolute calibration accuracy on the characteristics of the switch used in the equipment for calibrating calorimeters. When calibrated at lower energies, the accuracy of the button swieth is higher than that of a silicon pontrolled switch.

A brief introduction is given to the exhibition on the scientific research achievements sponsored by Academia Sinica from Nov. 27, 1982 to Jan. 8, 1983, with emphasis laying on laser applications in medical science, industry, space and optical fiber communication.

Three methods for discriminating the radiative spectral characteristics are discussed which use the eoherence,distribution of radiative spectram as well as a dip in the side light spontaneous emission.

The results on animal test show that He-Cd laser irradiation could shorten the healing process of the wound induced by a CO2 laser.