Low phonon energy, Nd:LaF3 channel waveguide lasers fabricated by molecular beam epitaxy

We report the first fabrication and laser operation of channel waveguides based on LaF₃ planar thin films grown by molecular beam epitaxy. To our knowledge, this is the lowest phonon energy dielectric material to have shown guided-wave laser operation to date. A full characterization, in terms of spectroscopy, laser results, and propagation losses, is given for the planar thin films upon which the channel waveguides are based. Two channel-fabrication methods are then described, the first involves ion milling and the second takes the novel approach of using a photo-definable polymer overlay. Laser operation in Nd-doped samples is demonstrated at 1.06, 1.05, and 1.3 μm, and the potential for mid-infrared laser sources based on such guides is discussed