ABSTRACT
We report on the composition of Er-doped KGdxYbyY1-x-y(WO4)2 layers to be grown onto undoped KY(WO4)2 substrate providing fine lattice matching and high refractive index contrast with the substrate and fabrication of high optical quality Er(1.3 at. %):KGd0.2Yb0.15Y0.65(WO4)2 epitaxial layers with thickness up to 180 µm. Absorption and luminescence properties of the layer were measured and laser action under direct in-band pumping was reported for the first time, to our knowledge, in a non-waveguide configuration. A maximum output power of 16 mW with slope efficiency of 64% was achieved at 1606 nm.
ABSTRACT
A single-layer graphene saturable absorber is employed for passive Q-switching of an Er, Yb:GdAl3(BO3)4 (Er,Yb:GdAB) compact laser, representing the first Er-doped oxoborate laser Q-switched by graphene. This laser is based on a c-cut 1.8 at. % Er3+, 15 at. % Yb3+:GdAB crystal diode-pumped at 0.976 µm. It generates a maximum average output power of 360 mW at 1.55 µm with a slope efficiency of 23% (with respect to the incident power). Stable â¼1 µJ/130 ns pulses are achieved at a repetition rate of 400 kHz. This result represents, to the best of our knowledge, the shortest pulse duration ever achieved in bulk Er lasers Q-switched by 2D materials. Graphene is a promising material for generating nanosecond pulses at high repetition rates (MHz range) in Er-doped oxoborate lasers emitting in the eye-safe range at 1.5-1.7 µm.
