Polarized spectroscopy and SESAM mode-locking of Tm,Ho:CALGO

A Tm,Ho:CALGO laser passively mode-locked by a GaSb-based SESAM generated pulses as short as 52 fs at a central wavelength of 2015 nm with a broad spectral bandwidth of 82nm (full width at half maximum) owing to the combined gain profiles of both dopants for sigma-polarized light. The average output power reached 376 mW at a repetition rate of 85.65 MHz. In the continuous-wave regime, the laser was power scaled up to 1.01 W at 2080.6 nm with a slope efficiency of 32.0%, a laser threshold of 155 mW and pi-polarized emission. Polarized spectroscopic properties of Ho3+ ions in singly doped and codoped CALGO crystals were revisited to explain the observed laser performance. (C) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

Automated summary

In this study, a Tm,Ho:CALGO laser passively mode-locked by a GaSb-based SESAM is reported. The laser generates pulses as short as 52 fs, with a central wavelength of 2015 nm and a broad spectral bandwidth of 82 nm. The laser performance is attributed to the combined gain profiles of the dopants and the polarized spectroscopic properties of Ho3+ ions.