“Mixed” Tm:Ca(Gd,Lu)AlO 4 — a novel crystal for tunable and mode-locked 2 µm lasers

Identifier:  imarina:4908732

Handle: https://hdl.handle.net/20.500.11797/imarina4908732

Authors:  Pan, ZB; Loiko, P; Serres, JM; Kifle, E; Yuan, HL; Dai, XJ; Cai, HQ; Wang, YC; Zhao, YG; Aguiló, M; Díaz, F; Griebner, U; Petrov, V; Mateos, X

Abstract:
© 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement. We report on the crystal growth, spectroscopy characterization and first laser operation of a new tetragonal disordered “mixed” calcium aluminate crystal, Tm:Ca(Gd,Lu)AlO 4 . The introduction of Lu 3+ leads to an additional inhomogeneous broadening of Tm 3+ absorption and emission spectra compared to the well-known Tm:CaGdAlO 4 . The maximum stimulated-emission cross-section for the 3 F 4 → 3 H 6 Tm 3+ transition is 0.91 × 10 −20 cm 2 at 1813 nm for σ-polarization, and the emission bandwidth is more than 200 nm. A continuous-wave diode-pumped Tm:Ca(Gd,Lu)AlO 4 laser generates 1.82 W at 1945 nm with a slope efficiency of 29%. Under Ti:Sapphire laser pumping, a continuous tuning of the laser wavelength from 1836 to 2083 nm (tuning range: 247 nm) is demonstrated. The Tm:Ca(Gd,Lu)AlO 4 crystal is promising for tunable/femtosecond lasers at ~2 μm.