Abstract

In the recent years a significant amount of effortsare focused on the development of single-frequency nanosecond and sub-nscompact lasers providing high energy (>1 mJ) and high average power(>1W) simultaneously. Q-switched, single frequency and single transverse mode lasers are essential for wide variety of applications [1] such as laser-induced breakdown spectroscopy, LIDARs, optical communications and laser trapping or cooling. The spatial dimension of conventional solid state Q-switched lasers precludes producing single frequency pulses with sub-nanosecondor few-ns duration. Although the short-cavity, passively Q-switched microchip lasers allow oscillations in single longitudinal- mode and generation of ~1 ns pulses devices their applicability is limited due to the inherent non-saturated losses in the absorber, which impose considerable limitation over achieving average power levels (~100mW) and poor ability for synchronization of the laser pulses with external electrical signals[1]. Micro lasers with active Q-switching overcome easily the intra-cavity losses and time jitter issue in the laser synchronization. However, the introduction of an active modulator leads to increase of the optical length of the cavity and therefore obtaining single frequency operation is more difficult and requires a different approach[2]. Consequently, a laser generating ~1-nanosecond, single frequency, TEM₀₀, milli-joule pulses with kHz repetition rate and high average power (≥ 1W) is at high demand.

© 2015 IEEE