Very low threshold laser operation of an epitaxially grown Nd:YAG waveguide

The use of optical waveguide geometries to maintain small spot sizes/high intensities over relatively long lengths can lead to high amplifications per unit pump power and low laser thresholds in laser-ion-doped materials. This has been successfully demonstrated in glass optical fibres, and recently much work has been carried out on crystal host waveguides. Here we report the fabrication and low threshold laser operation of a very low loss Nd:YAG planar waveguide grown by liquid phase epitaxy.