Highly efficient CW Tm,Ho:GdVO 4 laser pumped by a diode

Abstract

In this paper, we report a high efficient and high power continuous wave diode-pumped cryogenic Tm(5% at.), Ho(0.5% at.):GdVO 4 laser. One pumping source of Tm,Ho:GdVO 4 laser is a fiber-coupled laser diode with fiber core diameter of 0.4 mm and numerical aperture (N. A.) of 0.3, supplying 14.8 W power at 793.6 nm. Another fiber-coupled LD radiation wavelength is centered at 805 nm with 0.22 N.A. and the same core diameter delivering power of greater than 30 W. For input pump power of 13.6 W at 794.2nm, the maximum output power of 4.2W, optical-to-optical conversion efficiency of 31% and slope efficiency 38% have been attained at 2.048 µm. The maximum cw power of 7.9-W is achieved by 805 nm LD under power of 26 W, corresponding to 40% optical-optical conversion efficiency relative to absorbed pumping power, which is close to quantum limited efficiency of 2 µm laser.

Resonantly diode pumping of Tm:CaF2 and Tm:Ho:CaF2 lasers

“…[1] Efficient high power operation with thulium and thulium-holmium doping, based on direct laser-diode pumping was previously attained using laser diodes operating at 0.8 µm in hosts such as YLF, YAP and GdVO 4 . [2][3][4][5] To reduce the thermal effect and to increase the laser efficiency the resonant pumping directly to the upper laser band was also adopted. [6,7] In present study we demonstrate for the first time the direct diode resonant pumping of room-temperature operating Tm:CaF 2 and Tm:Ho:CaF 2 ceramics.…”