A repetitively pulsed xenon chloride excimer laser with all ferrite magnetic cores (AFMC) based all solid state exciter

摘要

Performance of repetitively pulsed xenon chloride excimer laser (lambda-308 nm) with solid state pulser consisting of magnetic pulse compression circuit (MPC) using all ferrite magnetic cores (AFMC) is reported. Laser system suitable for 100 Hz operation with inbuilt pre-ionizer, compact gas circulation and cooling has been developed and presented. In this configuration, high voltage pulses of similar to 8 mu s duration are compressed to similar to 100 ns by magnetic pulse compression circuit with overall compression factor of similar to 80. Pulse energy of similar to 18 J stored in the primary capacitor is transferred to the laser head with an efficiency of similar to 85% compared to similar to 70% that is normally achieved in such configurations using annealed met-glass core. This is a significant improvement of about 21%. Maximum output laser pulse energy of similar to 100 mJ was achieved at repetition rate of 100 Hz with a typical pulse to pulse energy stability of +/- 5% and laser pulse energy of 150 mJ was generated at low rep-rate of similar to 40 Hz. This exciter uses a low current and low voltage solid state switch (SCR) that replaces high voltage and high current switch i.e, thyratron completely. The use of solid state exciter in turn reduces electromagnetic interference (EMI) effects particularly in excimer lasers where high EMI is present due to high di/dt. The laser is focused on a thin copper sheet for generation of micro-hole and the SEM image of the generated micro hole shows the energy stability of the laser at high repetition rate operation. Nearly homogeneous, regular and well developed xenon chloride (XeCl) laser beam spot was achieved using the laser. (C) 2016 Elsevier Ltd. All rights reserved.