2.3 micron laser operation at room temperature, flash lamp pumped Tm;Cr:YAG and Tm;Cr:YALO3 has been initially reported in 1975 by Caird et al. We could not find any records of continuation of work in this direction, probably because of the low efficiency reported in YAG and lack of high quality YAP crystals. Cascade operation at 2 and 2.3 micron in diode pumped Tm:YLF has been also reported by Kintz et al. In our paper we present theoretical evaluation and experimental results from our work. We extracted more than 150 mJ at 2.32 micron at room temperature in Tm;Cr:YAG-flash lamp pumped at 30 Hz and 15 mJ at 60 Hz.
"2.32-micron flash-lamp-pumped high-repetition-rate laser operation in Tm;Cr:YAG", Proc. SPIE 1627, Solid State Lasers III, (1 June 1992); doi: 10.1117/12.60148; https://doi.org/10.1117/12.60148