Efficient Micro-Lasers Based on Highly Doped Monoclinic Double Tungstates

Identifier:  PC:2834

Handle: https://hdl.handle.net/20.500.11797/PC2834

Authors:  Xavier Mateos; Pavel Loiko; Josep Maria Serres; Konstantin Yumashev; Uwe Griebner; Valentin Petrov; Magdalena Aguiló; Francesc Díaz

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 efficientmicro-lasers at ¿1 ¿m and at ¿2 ¿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 ¿ = 77%. The quantum efficiency for Tm3+ ions amounted to ¿q = 1.98±0.02. With a 0.9 mm-thick 25 at.% Yb:KLuW micro-laser, ¿ = 91% is achieved, approaching the theoretical limit set by the Stokes shift.