Efficient infrared (≈1.9-2.0 μm) laser operation in color-defect-free Tm:NaGd(MoO4)2 crystal

Abstract

Color-defect-free 5 at.% Tm:NaGd(MoO4)2 crystals have been grown in a Na2MoO4/Na2Mo 2O7 flux. Using a hemispherical optical cavity and pumping at λ = 794.5 nm with a Ti-sapphire laser, up to 850 mW of output power at λ ≈ 1900 nm was obtained at 300 K with an output coupler transmission of 8%. In the cw regime, the slope efficiency versus absorbed power was η = 45% and the pump power laser threshold was ≈180 mW. The laser was tunable from 1875 to 1975 nm and the emission had a FWHM bandwidth ≈20 nm, indicating the potential for ultrashort laser pulse generation. © 2013 Astro Ltd.