High temperature operation of passively Q-switched, Cr:YAG/Nd:YAG micro-laser for ignition of engines

This paper presents the fabrication of compact, high-brightness, passively Q-switched micro-lasers and end-pumped by fiber-coupled laser diodes. The micro-laser brightness is calculated as 0.3 PW/sr-cm
²
and the focused optical power intensity is estimated as 5 TW/cm
²
at the pulse energy of 2.7 mJ. The 600-ps short pulse width and high beam quality (M
²
=1.2) has the capability of reducing ignition energy and laser head size, comparable to that of a spark plug. These Cr:YAG/Nd:YAG micro-lasers are developed for the ignition of engines, especially for automobile engines. Finally, high temperature (>100degC) operation of the passively Q-switched micro-laser is tested and analyzed.