Growth, spectroscopy and 2 μm laser operation of monoclinic Tm3+:ZnWO4 crystal

Identifier:  imarina:9382529

Handle: https://hdl.handle.net/20.500.11797/imarina9382529

Authors:  Elabedine, GZ; Subbotin, K; Loiko, P; Pan, ZB; Eremeev, K; Zimina, Y; Didenko, Y; Pavlov, S; Titov, A; Dunina, E; Fomicheva, L; Kornienko, A; Braud, A; Solé, RM; Aguiló, M; Díaz, F; Chen, WD; Volkov, P; Petrov, V; Mateos, X

Abstract:
We report on the crystal growth, polarized spectroscopy, and laser operation of monoclinic Tm3+, Na+(Li+) codoped zinc monotungstate (ZnWO4) crystals. The Li+ codoping with an optimized Tm/Li ratio enables almost complete local charge compensation leading to better crystal quality, higher Tm segregation coefficient, and longer luminescence lifetime and ultimately the demonstration of laser operation. The modified Judd-Ofelt theory was employed to calculate the Tm3+ transition probabilities yielding a radiative lifetime of the F-3(4) state of 2.59 ms. The corresponding intensity parameters are Omega(2) = 5.194, Omega(4) = 0.658, Omega(6) = 0.471 [10(-20) cm(2)] and alpha = 0.110 [10(-4) cm]. Tm,Li:ZnWO4 features strongly polarized emission spectra extending beyond 2 mu m owing to a large total Stark splitting of the ground-state, Delta E (H-3(6)) = 644 cm(-1). The stimulated-emission cross-section in this spectral range reaches 0.47 x 10(-20) cm(2) at 2015 nm for light polarization E || N-p. The continuous-wave Tm,Li:ZnWO4 laser generated 282 mW at 1.98 mu m with a slope efficiency of 14.7 %, and laser emission at 2.03 mu m was also achieved.