Research on optimum slowly-rising driver for electro-optic Q-switched laser

Abstract

Electro-optic Q-switch drivers that based on pulse transformer method have been widely used in laser engineering because of the advantages of concise circuits, low supply voltage, low lost, etc., but the long rise time and short pulse duration of the high voltage (HV) pulses have a considerable effect on the Q-switched laser outputs. In this paper, we experimentally investigated the dependence of Q-switched laser outputs on the rise rate of slowly-rising HV pulses in a flash pumped Nd:YAG laser with variable cavity lengths. LiNbO3 Q-switches with various dimensions were used. Based on the experiment results, the optimum slowly-rising HV pulses for any EO Q-switched laser were derived, the only requirement is that voltage near dynamic quarter-wave voltage during the emission of laser pulses. Additionally, the optimum outputs were found to be consistent with the results obtained by using a rapid-switching driver with a rise time of 7 ns. The optimum range of applied voltage was determined to be 0.88–1.12 times dynamic quarter-wave voltage.