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arXiv · 1901.07737

Tm-doped Crystals for mid-IR Optical Cryocoolers and Radiation Balanced Lasers

Saeid Rostami·Alexander R. Albrecht·Azzurra Volpi·Markus P. Hehlen·Mauro Tonelli·Mansoor Sheik-Bahae
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Abstract

We report the complete characterization of various cooling grade Tm-doped crystals including the first demonstration of optical refrigeration in Tm:YLF crystals. Room temperature laser cooling efficiencies of 1% and 2% (mol) Tm:YLF, and 1% Tm:BYF crystals at different excitation polarizations are measured and their external quantum efficiency and background absorption are extracted. By performing detailed low-temperature spectroscopic analysis of the samples, global minimum achievable temperatures of 160 K to 110 K are estimated. The potential of Tm-doped crystals to realize mid-IR optical cryocoolers and radiation balanced lasers (RBLs) in the eye-safe region of the spectrum is discussed, and a promising 2-tone RBL in a tandem structure of Tm:YLF and Ho:YLF crystals is proposed.

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Saeid Rostami, Alexander R. Albrecht, Azzurra Volpi, Markus P. Hehlen, Mauro Tonelli, Mansoor Sheik-Bahae. 2019-02-22. Tm-doped Crystals for mid-IR Optical Cryocoolers and Radiation Balanced Lasers. https://doi.org/10.1364/ol.44.001419

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