Tm:KY1-x-yGdxLuy(WO4)(2) planar waveguide laser passively Q-switched by single-walled carbon nanotubes

Abstract

A Tm3+ monoclinic double tungstate planar waveguide laser is passively Q-switched (PQS) by a saturable absorber (SA) based on single-walled carbon nanotubes (SWCNTs) randomly oriented in a polymer film. The laser is based on a 18 mu m-thick 5 at.% Tm:KY1-x-yGdxLuy(WO4) 2 active layer grown on an undoped (010)-oriented KY(WO4) 2 substrate by liquid phase epitaxy with determined propagation losses 0.7 +/- 0.2 dB/cm. The PQS laser generated a maximum average output power of 45.6 mW at 1.8354 mu m with a slope efficiency of 22.5%. Stable 83-ns-long laser pulses with an energy of 33 nJ were achieved at a repetition rate of 1.39 MHz. The use of SWCNTs as SA is promising for generation of sub-100 ns pulses in such waveguide lasers at similar to 2 mu m. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement