A SYSTEMATIC STUDY ON LASER CHARACTERISTICS OF GAS-LASER BY MEANS OF THE SHOCK TUBE

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In case of employing a wedge nozzle for CO2 Gasdynamic Laser, the Laser power depends on a distance from nozzle throat and there is the optimum distance where the Laser power is the largeset. This caracteristics is because of the oblique shock wave. The existance of the oblique shock wave was confirmed by the flow visualization experiments. Two-dimentional mumelical analysis which considers the influence of the oblique shock wave was carried out. In the shock wave configuration, good agreement between the results of flow visualization and calculation was obtaind. Experimental value of small signal gain coefficient agreed well with the calculated one. Consequently, the influence of the oblique shock wave is as follows : Translational temperature of the Laser gas increases behind the oblique shock wave. Therefor, the population inversion becomes extinct and the small signal gain is decreased. The Laser medium is reheated by passing through the oblique shock wave.in order to carry out an experimental study on an after-mixing Gasdynamic Laser, experimental apparatus was designed. That was made up of two diaphragm type shock tubes. In the case of after-mixing type Gasdynamic Laser experiments by using these xhock tubes, it is necessary to synchronize the stagnation conditions. it is difficult to synchronize two stagnation conditions by using a conventional diaphragm type shock tube, however, this experimental apparatus enables to synchronize them. Small signal gains and Laser powers were measured by using the above apparatus. This result appears to be useful for the shock tube technique.It is necessary to study the themophysical properties of high temperature gases which are used for Gasdynamic Laser. In this research, as the first step of the further study, the themal conductivity of high temperature gases were measured by the shock tube.