Excited-state absorption and upconversion pumping of Tm³⁺-doped potassium lutetium double tungstate

Aleksey Tyazhev (1) , Pavel Loiko (2) , Lauren Guillemot (2) , Alexandre Kouta (1) , Rosa Maria Solé (3) , Xavier Mateos (3) , Magdalena Aguiló (3) , Francesc Díaz (3) , Hippolyte Dupont (4) , Patrick Georges (4) , Frédéric Druon (4) , Alain Braud (2) , Patrice Camy (2) , Ammar Hideur (1)

1 CORIA - Complexe de recherche interprofessionnel en aérothermochimie
2 CIMAP - UMR 6252 - Centre de recherche sur les Ions, les MAtériaux et la Photonique
3 FiCMA - Física i Cristal·lografia de Materials i Nanomaterials
4 Laboratoire Charles Fabry / Lasers

We report on a bulk thulium laser operating on the 3 H 4 → 3 H 5 transition with pure upconversion pumping at 1064 nm by an ytterbium fiber laser (addressing the 3 F 4 → 3 F 2,3 excited-state absorption (ESA) transition of Tm 3+ ions) generating 433 mW at 2291 nm with a slope efficiency of 7.4% / 33.2% vs. the incident / absorbed pump power, respectively, and linear laser polarization representing the highest output power ever extracted from any bulk 2.3 µm thulium laser with upconversion pumping. As a gain material, a Tm 3+-doped potassium lutetium double tungstate crystal is employed. The polarized ESA spectra of this material in the near-infrared are measured by the pump-probe method. The possible benefits of dual-wavelength pumping at 0.79 and 1.06 µm are also explored, indicating a positive effect of co-pumping at 0.79 µm on reducing the threshold pump power for upconversion pumping.

Domaines: Physique [physics]

Aleksey Tyazhev, Pavel Loiko, Lauren Guillemot, Alexandre Kouta, Rosa Maria Solé, et al.. Excited-state absorption and upconversion pumping of Tm³⁺-doped potassium lutetium double tungstate. Optics Express, 2023, 31 (9), pp.14808-14820. ⟨10.1364/oe.487130⟩. ⟨hal-04247290⟩