Performance of a 2-μm laser in Tm:YAG grown by a laser-heated pedestal growth technique

Abstract

The laser-heated pedestal growth (LHPG) technique for rapid growth of laser crystals can provide small crystal rods at a lower cost than can bulk-growth methods. We have been able to grow a variety of rare-earth-doped garnets and fluorides. Controlled doping was achieved by mixing powdered dopant and host materials in our feedstock preparation. In this paper we report laser performance in Tm:YAG with a sample grown at our facility. The 3% doped sample was 1 mm in diameter and 3 mm long. The minirod had flat and parallel surfaces with an antireflection coating at 2 μm. An argon-pumped Ti:sapphire laser operating at 785 nm was used to end-pump the laser crystal, which was placed in a piano-concave resonator. With 6% output coupling, room temperature operation of this cw laser was observed at a threshold of 75 mw of absorbed pump power at a slope efficiency of 51%. This performance compared favorably with the performance of lasers using bulk-grown Tm:YAG crystals. We have shown that laser-quality crystals can be obtained with this growth method, which will allow us to rapidly study new laser host/dopant/codopant combinations.