Design and modeling of a passively Q-switched diode-pumped Thulium laser at 2.3 μ m

Esrom Kifle (1) , Pavel Loiko (2) , Lauren Guillemot (2) , Jean-Louis Doualan (1) , Florent Starecki (1) , A. Braud (2) , Ammar Hideur (3) , Patrice Camy (2)

1 CIMAP - UMR 6252 - Centre de recherche sur les Ions, les MAtériaux et la Photonique
2 OML - Optique, Matériaux et Laser
3 CORIA - Complexe de recherche interprofessionnel en aérothermochimie

We report on a diode-pumped Tm:LiYF4 laser operating on the 3H4 → 3H5 transition (at ◂,▸∼2.3μm) passively Q-switched by a Cr2＋:ZnSe saturable absorber. This laser delivers a maximum average output power of 130 mW at 2304.6 nm with a nearly diffraction limited beam, a linear polarization (π) and no colasing at ◂,▸∼1.9μm. The corresponding pulse characteristics (duration/energy) are 1.24 μs/3.6 μJ at a repetition rate of 36 kHz. By power scaling under quasi-CW pumping, even shorter pulse durations of 870 ns and higher pulse energies of 6.1 μJ are achieved. The performance of the laser is simulated using a model of a quasi-four-level gain medium and a “slow” saturable absorber showing a good agreement with the experiment. The effect of the thermal lens of the saturable absorber on the pulse characteristics is discussed.

Mots clés: Diode-pumped laser; Thulium ions; Passive Q-switching; Mid-infrared; Laser transition

Domaines: Optique [physics.optics]; Science des matériaux [cond-mat.mtrl-sci]

Esrom Kifle, Pavel Loiko, Lauren Guillemot, Jean-Louis Doualan, Florent Starecki, et al.. Design and modeling of a passively Q-switched diode-pumped Thulium laser at 2.3 μ m. Optics Communications, 2021, 500, pp.127219. ⟨10.1016/j.optcom.2021.127219⟩. ⟨hal-03345651⟩