Self-Q-switched σ-polarized Tm,Ho:CaLu0.1Gd0.9AlO4 laser at 2.1 μm

Abstract In the present work, we report the first demonstration of a novel Thulium and Holmium (Tm,Ho) co-doped tetragonal CaLu0.1Gd0.9AlO4 (CLGA) disordered crystal pulsed laser at 2.1 μm. The spectroscopic investigation indicated that the emission of the grown Tm,Ho:CLGA disordered crystal in the σ-polarization possessed a more smooth spectrum with a full-width at half-maximum (FWHM) of ∼300 nm. The stable self-Q-switching behavior was observed. With the output coupler of T = 1%, the minimum self-Q-switching pulse duration of 980 ns was obtained at 2091 nm with a maximum repetition rate of 41 kHz under an absorbed pump power of 4.26 W. The results confirmed that this new disordered Tm,Ho:CLGA crystal could be a promising candidate for the solid-state pulsed lasers at 2.1 μm.