Towards fabrication of 10 W class planar waveguide lasers: analysis of crystalline sesquioxide layers fabricated via pulsed laser deposition

Planar waveguides lasers are compact, power-scalable devices that have excellent thermal management properties owing to their high surface area to volume ratio [1]. However, the fabrication of these waveguides can be labour-intensive. A simple, versatile technique known as pulsed laser deposition combines tailored, uniform planar layer deposition with relatively high growth rates approaching 5µm per hour for our set-up. In this technique, a target material is ablated by a laser pulse, with the resultant plume incident onto the surface of a single-crystal substrate on which single crystal layers can grow [2]. We will present both the X-ray diffraction (XRD) analysis and laser performance of ytterbium-doped crystalline yttria (Yb:Y2O3) and undoped crystalline yttria thin films, grown on a variety of substrates using a 248 nm, 20 ns pulsed excimer laser operating at a repetition rate of 20 Hz.