Date of Award

1-1-2000

Thesis Type

Masters

Document Type

Thesis

Divisions

Faculty of Science

Department

Department of Physics

Institution

Universiti Malaya

Abstract

A novel discharge scheme is proposed for the pumping of short wavelen,gth lasers. This scheme had been tested to produce fast current pulse and a 5 kA current in 60 nsec is obtained. Lasing action has been observed by using nitrogen gas. The laser line is 337 nm from the strong transitions of nitrogen molecules. The new discharge scheme is based on the concept of an arc array amplifier. It essentially consists of 48 pairs of electrodes which are lined up to form an array of arc discharge. Its electrical circuitry allows each pair of the electrodes to be decoupled from the rest electrically. Each pair of the electrodes is fed by individual storage and peaking capacitors in an extended C-to-C charge transfer circuit. Such a configuration allows the system to have high current density with a fast rise-time. The electrical circuitry of this system was optimised with respect to the scalability to pump in higher current density in a faster pulse. The effect of the inductance and the capacitance of the system were investigated in the present project. The inductance of the system was minimized by carefully positioning every component of the system to minimize inductive current loop. The role of the spark gap has also being investigated to obtain a faster discharge. Different values of storage and peaking capacitances were used to obtain higher discharge current. It is found that a low inductance transfer loop between the storage and the peaking capacitors allows the peaking capacitors to charge up faster. resulting in higher breakdown voltage in the laser channel. Larger capacitance of each individual electrodes has also increased the current density. However. the optical power has dropped from 1.4 mJ by using 2 nF capacitor to 1.2 mJ for the case of 5 nF capacitor. This is due to the longer discharge pulse-width in the latter configuration. This study show that the new arc array discharge circuit is capable to generate laser output due to its fast discharge characteristic􀈡. More importantly, it has demonstrated a new way of electrical discharge pumping method 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 state of ionisation for output in the VUV and soft x-ray region.

Initial

snms

Additional Information

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

Download

Share

COinS