1200 nm pumped Tm3+:Lu2O3 ceramic lasers.

Abstract

We report on an experimental demonstration of a 1200-nm pumped Tm3+:Lu2O3 ceramic laser. By using a gain-switched, tunable Cr4+:forsterite laser, the excitation spectrum was measured, with optimum pumping bands centered near 1198nm, 1204nm, and 1211nm. The highest slope efficiency of 21.5% was obtained at the pump wavelength of 1204nm. Comparative energy efficiency measurements performed near 1200-nm and 800-nm pumping further showed that nearly 40% improvement was obtained in slope efficiency measured with respect to the incident pump energy for 1200-nm pumping. A transition was further observed from single-wavelength operation at 2066nm to dual-wavelength operation near 2066nm and 1967nm for absorbed pump energies above 50μJ. In this regime, two consecutive output pulses were observed in the time domain. The shortest temporal duration of the first pulse was 1.1μs at the incident pulse energy of 105μJ. The duration and build-up time of the second pulse remained around 5.9μs and 18.5μs. We believe that the improved energy efficiency demonstrated for the 1.5% Tm3+:Lu2O3 ceramic with 1200-nm pumping can be used as an alternative scheme for the excitation of Tm3+:Lu2O3 ceramic lasers.