An electrostatic probe and a boxcar are used to measure the electron density Ne and the electron temperature Te in TEA CO2 laser gas mixture, Ar and Ar-N2 under the condition of UV preionization. The time-dependent characteristics of ne and Te are studied. The experimental results show that the electron temperature decay is slower than the electron density decay. The preionization mechanism in CO2 laser gas mixtures is described.

This paper offers a new method for measuring the starting characteristic of the micromotor by laser doppler velooimetry. Its basic principle is discribed briefly. Some problems such as the measuring accuracy and tracking rate are emphasized and preliminary experiment is described. The advantages of this method are that it is unnecessary to load the micromotor, the measuring accuracy is high and the measuring process is fast.

The physics of optoelectronic switching under high voltage is discussed. Using the ultrashort pulse at 1.06 μm to control switching element, picosecond electrical pulse synchronized precisely with the mode-locked laser pulse is produced. Voltage up to 7 kV has been switched. This voltage has been used to drive a fast Pockets cell and the rise time of 56 ps has been obtained.

In this article the mathematical formulas for generating second order aspherio surfaces are derived. The aspheric surface to be worked is treated as an envelope of spheres with different radius of curvature at different zones. δp and αp are taken as parameters to describe the motion of grinding tool, where δp is the distance between vertex of surface and lowest point of the tool; and αp is the angle between tool axis and aspheric surface axis. In order to realize the design of practical machine, it is convenient to change the angle aP around a point M oil tool axis rather than any other point. So that the equations for determining the coordinates of point M are also derived. In the case of mass production, pure mechanism is better than computer control of tho grinding machine and the best mechanism seems to be cam pair, because such mechanism makes the grinding process repeatable and it is possible to produce a smooth aspherical surface. So that th? mathematical equations for cam design are also given.

The charge-transfer collision spectroscopy of He+-Cd and He+-Zn were studied by using crossed-beam technique. The results may be divided into two parts: (1) The resonant collision cross-sections for the energy defect less than 1 eV, which are consistent with the known theory; (2) The 4d9s2 configuration in Cd+ and 3d9s2 in Zn+ are strongly excited and it means that CT collision has important contribution to the population inversion mechanism of 441.6 and 325.0 nm laser lines in Cd+ and of 747.9 and 589.4 nm nm lines in Zn+. The resonant OT collision followed by cascade radiation may be responsible to this contribution.

The radiation density operator theory and perturbation method are used to obtain the master equation of the three-mode laser operation in a homogeneously broadened medium consisting of four-level atoms by means of a generalizasion of the Lamb fully quantum-mechanical theory. Meanwhile diagrams of probability flow are drawn. By considering and reasonablly understanding the principle of detailed balance, the equations of motion in steady states are obtained. The operation characteristics and the quantum-statistical properties of the lager under different conditions are discussed. Especially the calculations of the photon number distributions are carried out numerically, so that the results are given in detail and the comparison is easily carried out. Furthermore, by taking into account the equation of motion for the off-diagonal elements of the radiation density operator, the laser line-widths in different oases of gingle-mode, two-mode and three-mode are given and compared.

The free electron laser with a linearly polarized wiggler and axial guide field hag been studied. A relativistio, cold electron beam passes through a parallel-plate waveguide in these magnetic fields. The spontaneous emission coefficient and the dispersion equation of the stimulated Raman emission of the transverse electric wave (TE mode) in the electron beam reference-frame are calculated. It s growth rate is given. When the cyclotron frequency of the electron is equal to the frequency of the pump wave in the electron beam referenoe-frame, the intensities of both the sponliarieous and stimulated emissions increase sharply due to the resonance.

Using linearly polarized dye laser beam which is tuned between the doublet on Na to excite Na vapor, a conical emission with polarization perpendicular to that of the incident laser in the forward direction has been observed. Its spectrum and the time evolution are measured. The relation between this emission and the density of Na, the parameters of laser and the pressure of the buff re gas have been studied. This phenomena may be explained by considering the coupling of Rayleigh scattering and transient field of Na atom.

A dynamical growth model of MBE (Molecular Beam Epitaxy) is discussed. A surface characterization method, i. e. HEED, is used to support this model. GaAs is taken as an example to investigate the MBE growth rate and its dependence on Ga flux by using the quadrupole mass spectroscopy. A suitable ratio of partial pressure of Ga to that of Al is studied theoretically and experimentally for growing Ga1-x Alx As materials with particular values of X. The dependences of doping concentrations in Si-, Sn-, and Be—doped GaAs on the temperatures of their effusion cells are given respectively.

Time-dependences of the beam intensity profile along the m lines of different waveguides which prepared by use of various methods were measured. The result demonstrated that the waveguides by ion migration had higher resistance ability of optical damage. These waveguides were prepared by use of the salt bath method in AgNO3 by applying electrical field proposed by Y. X. Chen et al. and the C6H5COOH melt bath method of Bell Lab. When optical damage arises, the anglular width of propagating beam in this waveguide which produced by in-plane scattering could reach to 40°. In rogard to the relation between th? method of formation of the waveguide and its resistance ability of optical damage, author proposes that when one method makes oxidized state of impurities ions tend to more stable, in other words, increasing Fe+++/Fe++ (or Cu++/Cu+，Mn++)ratio, the resistance ability of optical damage of the waveguide prepared "by such method is higher. Otherwise when waveguides are easy contaminated by impurities in preparation process, the resistano? ability of optical damage is lowor. In addition at high operation temporature (specially close Ourie point) the transformation could take place, thus the resistance ability of optical damage is lower.

Polarization properties of single-mode fibers have been investigated by using the differential Jones-matrices. The differential Jones vector equation is derived, then the representation theory of differential Jones-matrix is introduced. Applying then to complex multiply perturbed single-mode fibers, the expressions of birefringence and evolution of polarization are found to be very simple and quite intuitive. The formula for polarization evolution of twisted fibers with an elliptical core is given.

For solid state lasers with lower order mixing modes in which TEM00 mode is dominant and a few lower order modes are included, a method of dealing with the beam based on Gaussian-like distribution is presented. The beam of lower order mixing modes may be regarded as a fundamental mode Gassian beam expanded K times. (K is the multimode coefficient). Firstly, from the calculation of intensities and spot sizes of the mixing modes and the fundamental mode, the justification of this assumption is indicated. Then the calculating formulae for the beam characteristics of the mixing modes are given.. By Gaussian-like method, a typical oontinuous waye YAG laser is analysed and the region of the optimum oayitv length is found. After that, the experimental method of measuring the value of K is recounted. Finally, the coupling of the laser output beam with a fiber is discussed, the necessary parameters for the practical application are obtained.

Mechanism and condition of single longitudinal mode operation of the semiconductor lasers with external dispersive cavity have been investigated theoretically and experimentally. Using multimode laser diodes with unooating facet as well as coating facet, stable single longitudinal mode is obtained under room temperature CW opera- tion. Its linewidth is less than 10-3 A(50 MHz) and the tunable range is 200 A. Single mode output power is more than the total power output of multimode with our external cavity up to 3 mW.

This paper presents a method of measuring the total integrated scattering (TIS) from laser films. Some experimental results obtained by weak signal phase look-in synchronism technique are given. This method can be used to study the surface micro-Structure of the optical components. The detective sensitivity of this equipment is better than 10-5, The TIS of about 1.5?10-3 for high reflectivity films is measured.

An analytical model for sensitized fluorescence has been developed. Some electron collisional transfer rates between excited states of the atom can be calculated from this model using experimental data of both sensitized and direct resonant fluorescence. As an example, the collisional transfer rate from 33D to 33D and the total de-excitation rate of 33P of neutral helium have been determined with this method in a partially ionized helium plasma in which the electron density and electron temperature are 5×10 14 cm-3 and 1.1 eV respectively.

This paper gives an expression of the two nonzero elements of M(1)n+1 Matrices in tho Fast Hadamard Transform. The methods of formula decoding and fast decoding in tho Hadamard transform spectroscope are also given.