A repetitively pulsed xenon chloride excimer laser with all ferrite magnetic cores (AFMC) based all solid state exciter. (October 2016)

• Record Type: Journal Article
• Authors: Benerji, N.S.; Varshnay, N.K.; Ghodke, D.V.; Singh, A.
• Is Part Of: Optics & laser technology. Volume 84(2016)
• Page Start: 72
• Page End: 78
• Publication Date: 2016-10
• Subjects: Excimer laser -- All solid state pulser -- Magnetic pulse compression -- Ferrites; Optics -- Periodicals; Lasers -- Periodicals; Electronic journals; 621.366
• DOI: 10.1016/j.optlastec.2016.05.004
• Languages: English
• ISSNs: 0030-3992

Abstract

Abstract: Performance of repetitively pulsed xenon chloride excimer laser (λ~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 ~8 µs duration are compressed to ~100 ns by magnetic pulse compression circuit with overall compression factor of ~80. Pulse energy of ~18 J stored in the primary capacitor is transferred to the laser head with an efficiency of ~85% compared 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 ~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 ~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. Highlights: We demonstrate all ferrite based HV exciter in an excimer laser for the first time. Elimination of thyratron with simple, inexpensive and efficient high voltage pulser. Homogeneous and completely filled excimer laser output beam was achieved. SEM image shows generation of clean micro hole and stability of laser energy. The all solid state pulser is rugged and easy to assemble.