Abstract

We experimentally demonstrate, for the first time to our knowledge, that upconversion pumping can be employed with a 1064-nm fiber laser to achieve tunable laser operation with 8 at. % ${\rm{T}}{{\rm{m}}^{3 +}}{:}{{\rm{KY}}_3}{{\rm{F}}_{10}}$ crystal near 1.9 µm, in addition to the previously explored upconversion pumping of the 2.3-µm laser transition. Two different sets of cavity optics were used to investigate lasing at 1.9 and 2.3 µm, corresponding to the laser transitions $^3{{\rm{F}}_4} {-} {^3{\rm{H}}_6}$ and $^{{3}}{{\rm{H}}_4} {-} {^3{\rm{H}}_5}$, respectively. In the case of the $^3{{\rm{F}}_4} {-} {^3{\rm{H}}_6}$ laser transition, an x-cavity laser oscillator was constructed with a 2.3% output coupler and as high as 142 mW of output power was obtained at an incident pump power of 1.9 W at 1064 nm. Tunable laser operation could be obtained between 1849 and 1994 nm by using ${\rm{Ca}}{{\rm{F}}_2}$ and suprasil prisms. The highest slope efficiency of 29% with respect to average absorbed pump power was obtained with a 5.5% output coupler. For the case of 1.9 µm lasing, it was further demonstrated that the nonlinear absorption of the crystal at 1064 nm depends on the intracavity laser intensity as well as the pump intensity. The $^{{3}}{{\rm{H}}_4} {-} {^3{\rm{H}}_5}$ laser transition was also investigated with the same crystal in a z-cavity configuration under upconversion pumping, giving as high as 130 mW of output power at the central wavelength of 2344 nm with 1.6 W of incident pump power.

© 2021 Optical Society of America

Highly efficient 2.3 µm thulium lasers based on a high-phonon-energy crystal: evidence of vibronic-assisted emissions

Pavel Loiko, Esrom Kifle, Lauren Guillemot, Jean-Louis Doualan, Florent Starecki, Alain Braud, Magdalena Aguiló, Francesc Díaz, Valentin Petrov, Xavier Mateos, and Patrice Camy
J. Opt. Soc. Am. B 38(2) 482-495 (2021)

Upconversion pumping of a 2.3 µm Tm³⁺:KY₃F₁₀ laser with a 1064 nm ytterbium fiber laser

Yagız Morova, Mauro Tonelli, Valentin Petrov, and Alphan Sennaroglu
Opt. Lett. 45(4) 931-934 (2020)

Watt-level diode-pumped thulium lasers around 2.3 µm

Esrom Kifle, Pavel Loiko, Lauren Guillemot, Jean-Louis Doualan, Florent Starecki, Alain Braud, Thierry Georges, Julien Rouvillain, and Patrice Camy
Appl. Opt. 59(25) 7530-7539 (2020)

Upconversion pumping of lasers via excited-state absorption: an analytical rate-equation formulation

Alphan Sennaroglu
J. Opt. Soc. Am. B 39(9) 2400-2406 (2022)

Tm:CALGO lasers at 2.32 µm: cascade lasing and upconversion pumping

Hippolyte Dupont, Pavel Loiko, Aleksey Tyazhev, Luidgi Giordano, Zhongben Pan, Hongwei Chu, Dechun Li, Bruno Viana, Ammar Hideur, Lauren Guillemot, Alain Braud, Patrice Camy, Patrick Georges, and Frédéric Druon
Opt. Express 31(12) 18751-18764 (2023)