Elliptically polarized, nanosecond dual-pulse Raman laser with tunable pulse interval and pulse amplitude ratio

Abstract

Dual-pulse solid state lasers with pulse interval of tens nanoseconds have been applied in laser-induced breakdown spectroscopy, laser drilling, medical treatment, and atmospheric monitoring. Here, a Yb:YAG/Cr4+:YAG/YVO4 passively Q-switched Raman laser has been developed for generating dual-pulse lasers with tunable pulse interval and elliptical polarization. Pulse interval and pulse amplitude ratio between peaks of satellite pulse and main pulse are controlled by adjusting the incident pump power (Pin). As Pin increases from 1.3 to 5.9 W, the pulse interval decreases from 63.1 to 36.3 ns, and the pulse amplitude ratio between peaks of satellite pulse and main pulse increases from 0.1 to 1.1 for dual-pulse Raman lasers. At Pin = 4.9 W, dual-pulse Raman laser with equal peak power of 1.7 kW and pulse interval of 40.2 ns is obtained. The pulse widths are 2.7 and 3.6 ns, and the pulse energy are 4.6 and 6.2 μJ for the main pulse and satellite pulse, respectively. The elliptical polarization with ellipticity tunable from 0.08 to 0.54 is obtained for dual-pulse passively Q-switched Raman laser as Pin increases. Such a nanosecond dual-pulse laser source has the potential to expand simple, compact portable and economical laser applications in various fields.