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

Identificador:  imarina:9299802

Handle: https://hdl.handle.net/20.500.11797/imarina9299802

Autors:  Tyazhev, Aleksey; Loiko, Pavel; Guillemot, Lauren; Kouta, Alexandre; Sole, Rosa Maria; Mateos, Xavier; Aguilo, Magdalena; Diaz, Francesc; Dupont, Hippolyte; Georges, Patrick; Druon, Frederic; Braud, Alain; Camy, Patrice; Hideur, Ammar

Resum:
We report on a bulk thulium laser operating on the 3H4 → 3H5 transition with pure upconversion pumping at 1064 nm by an ytterbium fiber laser (addressing the 3F4 → 3F2,3 excited-state absorption (ESA) transition of Tm3+ 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 Tm3+-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.