Approach for power scaling solid-state lasers with intracavity motion.

Matthew Eckold,Jacob I Mackenzie,W Andrew Clarkson

doi:10.1364/ol.42.000775

Abstract

Solid-state lasers are typically limited by adverse thermal effects within the gain medium. In this Letter we describe a new method for dramatically reducing thermal effects in an end-pumped solid-state laser by incorporating a rotating intracavity periscope in the resonator to spatially separate the lasing and thermal processes. In contrast with previous examples of moving solid-state lasers, our approach keeps the gain medium stationary, simplifying the heat removal arrangement. This scheme has been applied to an Nd:YAG laser, yielding an output power of 120 W at 1.064 μm, limited by available pump power. Analysis suggests that scaling to much higher power is feasible with the appropriate laser design.

Highlights

In an optically pumped solid-state laser the quantum defect between pump and laser photon creates an unavoidable heating effect, which, in some circumstances may be further exacerbated by parasitic spectroscopic processes such as energy-transferupconversion and excited-state absorption
The net result is an increase in temperature and associated thermal effects, which become increasingly problematic as pump power is increased, in end-pumped lasers [1]
This feature is exploited to good effect in so-called ‘heat capacity’ lasers [5] and to some extent in quasicw lasers, where laser emission and thermal effects are separated in time by adopting low-repetition-rate pulsed pumping

Summary

Introduction

In an optically pumped solid-state laser the quantum defect between pump and laser photon creates an unavoidable heating effect, which, in some circumstances may be further exacerbated by parasitic spectroscopic processes such as energy-transferupconversion and excited-state absorption. An alternative and very different strategy for scaling laser power exploits the fact that the build-up time for gain (i.e. threshold inversion density) is generally much shorter than the timescale for establishing thermal effects.

Results

Conclusion