The paper describes a three-electrode electric-discharge XeCl-laser, in which the discharge ignition takes place, when a high-voltage pulse is delivered to a middle control electrode, a capacitor bank of the main discharge is connected directly to two other electrodes. The three- electrode system of a double discharge formation provides a sequential in time breakdown of two discharge gaps followed by a general discharge current. The laser reached the high efficiency up to 3.7% with the fast commutation < 5% from the pump energy and a significant decrease of the load on the elements of the electric system of the laser pump supply.

The present work is the further evolution of our studies on wide-angle intracavity beaming in 3-10.6-micron gas lasers by space-time light modulators.

The effective laser generation depends greatly on pumping conditions. To provide fast uniform atomic or molecular levels excitation special mechanisms are often required. One of them is the use of a fast ionization wave (FIW) which gives high-excited uniform plasma due to its high propagation velocity and great values of E/p in it. In experimental works carried out at our laboratory, where we investigated both cathode and anode -directed waves, it was fo,.md dependence of ionizing wave velocity on an electrical potential of the high voltages electrode and gas pressure. There are several works in which FIW has been successfully used for laser pumping especially for lasers on self-terminated transitions. For example in our laboratory such wave was successfully applied for nitrogen laser pumping. Here investigation is focused on several phenomena in such waves and on theoretical models of FIW. The mechanism of wave propagation is closely connected with ionization processes inside the narrow structure of the wave front where the electrical field has the typical shape of solitary wave. The several models of ionizing wave are discussed. Using cross-section averaging of the basic equations a numerical code is developed for investigation of super - high velocity wave propagation. Our numerical model is based on the continuity equation for electron and on the modernized non-linear equations describing evolution of the electrical potential. Equations for electron energy and drift velocity are significantly improved. With the help of this model it is possible to investigate evolution of wave and to trace dependence of the propagation velocity, energy absorption and different atomic levels excitation on main parameters: voltage, gas pressure, radius of discharge tube, initial electron concentration. The model can be also applied to backward shock of lightning. Typical values of breakdown parameters in modeling were V=32 kV. p=l-SO ton, potential growth duration on high-voltage electrode of 10 ns.

The characters of combustion driven cw deuterium fluoride (DF) chemical laser with C2H4/NF3 reactant were numerically investigated. The numerical simulation was carried out using compressibility scaling method--a finite difference technique for the numerical integration of the steady and unsteady Navier-stokes equations for reactive flow. The small signal gain and the flow field were calculated. The numerical results shown that active zone length of the cw DF chemical laser with C2H4/NF3 is very long, which is about 6 cm, and the average cavity pressure is about 7 torr as the combustion pressure is about 1.5 atm. These results shown that the DF chemical laser with C2H4/NF3 is suitable for high cavity pressure performance.

On the basis of gain coefficient calculation it is shown that the frequency of the CO laser can not be continuously tuned over 5 - 8/tm region by means of increasing its pressure beacause of the resonant absorption of the R and P branches. Keywords: gain coefficient, continuously tuning, resonant absorption

A TEA CO₂ laser with multi-electrode-pair in one optical resonant cavity is being studied. This kind of laser can obtain the output of multi-light pulse-pairs of high- intensity, and time interval of the pulses can be continuously regulated. Measure of the velocity of high- speed moving objects and objective detection are analyzed in principle according to the technology of pulse coding. Applications in this kind of laser in holography interferometry is also introduced in this paper.

An overview of the excimer laser market shows the trend towards shorter operating wavelengths. The optical properties of vacuum ultraviolet materials are described and the design of a reflective fluoride multilayer coating for 157 nm is given. Practical considerations and techniques used for the coating manufacture are discussed. Results on coating performance and film properties are presented. Finally, a summary reviews the relevant aspects and salient points encountered during the project with an indication of the direction of any subsequent follow-up work.

This paper describes a series of analyses using the 3-d MINT Navier-Stokes and OCELOT wave optics codes to calculate beam quality in a COIL laser cavity. To make this analysis tractable, the problem was broken into two contributions to the medium quality; that associated with microscale disturbances primarily from the transverse iodine injectors, and that associated with the macroscale including boundary layers and shock-like effects. Results for both microscale and macroscale medium quality are presented for the baseline layer operating point in terms of single pass wavefront error. These results show that the microscale optical path difference effects are 1D in nature and of low spatial order. The COIL medium quality is shown to be dominated by macroscale effects; primarily pressure waves generated from flow/boundary layer interactions on the cavity shrouds.

For the past several years we have been developing diode laser-based diagnostics for the Chemical Oxygen Iodine Laser (COIL). These systems operate by scanning a tunable diode laser over complete absorption lines in species such as water and oxygen. In this paper we describe measurements of the collisional broadening and shifts of absorption transitions in both water and oxygen. These results have implications for the interpretation of data such as the flow temperature when the diagnostics are used on COIL systems.