Holmium thin-disk laser based on Ho:KY(WO4)(2)/KY(WO4)(2) epitaxy with 60% slope efficiency and simplified pump geometry

Identifier:  imarina:9242022

Handle: https://hdl.handle.net/20.500.11797/imarina9242022

Authors:  Mateos, Xavier; Lamrini, Samir; Scholle, Karsten; Fuhrberg, Peter; Vatnik, Sergei; Loiko, Pavel; Vedin, Ivan; Aguilo, Magdalena; Diaz, Francesc; Griebner, Uwe

Abstract:
We report on the first holmium (Ho3+) monoclinic double tungstate thin-disk laser. It is based on a 250 mu m thick 3 at. % Ho:KY(WO4)(2) active layer grown on a (010)-oriented KY(WO4)(2) substrate. When pumped by a Tm-fiber laser at 1960 nm with a single-bounce (single double-pass) pump geometry, the CW Ho:KY(WO4)(2) thin-disk laser generated 1.01 W at 2057 nm, corresponding to a slope efficiency eta of 60% and a laser threshold of only 0.15 W. Implementing a double-bounce (second double-pass) for the pump, the output of this laser was scaled to 1.57 W with eta=55%. The maximum stimulated emission cross section sigma(SE) of the Ho3+ ions in the epitaxial layer reaches 2.5x10(-20) cm(2) at 2056.5 nm for E parallel to N-m. The Ho:KY(WO4)(2) epitaxial structures are promising for multi-watt mode-locked thin-disk lasers at similar to 2.06 mu m. (C) 2017 Optical Society of America