Efficient Micro-Lasers Based on Highly Doped Monoclinic Double Tungstates

Identifier:  imarina:9242023

Handle: https://hdl.handle.net/20.500.11797/imarina9242023

Authors:  Mateos, X; Loiko, P; Serres, JM; Yumashev, K; Griebner, U; Petrov, V; Aguiló, M; Díaz, F

Abstract:
We demonstrate the suitability of monoclinic double tungstates (MDTs), KRE(WO4) 2, where RE = Gd, Y or Lu, doped with Nd3+, Yb3+, Tm3+, or Ho3+ ions and co-doped with Yb3+-Tm3+, or Tm3+-Ho3+ ion couples, for highly efficient micro-lasers at similar to 1 mu m and at similar to 2 mu m. This is facilitated by the use of high rare-earth doping levels (up to 15 at.% for Tm, 10 at.% for Nd, and 25 at.% for Yb) and a special crystal cut along the Ng-axis providing the thermal guiding. Record slope efficiencies for bulk MDT lasers are achieved for each studied ion. A 15 at.% Tm: KLu(WO4)(2) laser generated 785 mW at 1957. 1965 nm with a slope efficiency eta = 77%. The quantum efficiency for Tm3+ ions amounted to eta(q) = 1.98+/-0.02. With a 0.9 mm-thick 25 at.% Yb: KLuW micro-laser, eta = 91% is achieved,