Date of Award

1-1-2000

Thesis Type

Masters

Document Type

Thesis

Divisions

Faculty of Science

Department

Department of Physics

Institution

Universiti Malaya

Abstract

In almost all pulsed gas lasers, transverse electrical discharge is employed in the excitation of the atoms or molecules. These lasers normally employ discharge across a pair of common electrodes to provide large volume and uniform glow discharge. The scaling of output power in such lasers is obtained by increasing the volume of the discharge and also the pressure of the discharge gas. For this reason. the energy coupled into the discharge channel is kept low enough to avoid arcing. Under these circumstances, the electron temperature of such uniform glow discharge is not sufficient to produce excitation of VUV or X-ray lasers. Since VUV lasers and X-ray lasers require discharge at higher electron temperature, arc discharge becomes the most suitable candidate for pumping such short wavelength lasers. Thus, a new discharge method is developed in this project. The possibility of having laser act ion by transverse arc array is investigated. This new discharge concept is tested in nitrogen gas for laser action. It is shown that lasing condition can be achieved easily and also be setup easily. Different setups have been investigated to provide the lowest circuit inductance and thus faster discharge. The voltage and current characteristics of the discharge have been studied too. Other parameters such as pressure and output power have also been studied. Various electrode profiles have been investigated to compare the output energy and discharge characteristics The maximum output energy for this system is I. 70±0.0 I mJ and the optimum operating pressure is 55 mbar. The peak current measured at one of the electrodes is 2.13±0.01 kA and the current density is estimated to be 4.26±0.0 I kN cm2 A FWHM optical pulse of 5ns pulse width has been observed. This study shows that the new arc array discharge circuit can also lead to laser output due to its fast discharge characteristics. More importantly, it has demonstrated a new way of electrical discharge pumping of gases that can be scaled up to higher energy coupling through arc discharge. Further work is needed to scale up the input energy needed to pump gases to higher states of ionization to obtain output in the VUV and soft x-ray regions.

Initial

snms

Additional Information

Dissertation (M.A) -- Faculty of Science, Universiti Malaya, 2000.

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