Axisymmetric Laser Sources with Planar Gain Media

This project will investigate a new approach for generating axisymmetric laser output from active media with a planar geometry. A novel intracavity beam transformer will be employed to convert the highly elliptical cavity mode, with dimensions determined by the planar excitation volume, to a circular mode without degradation in brightness. This scheme will be applied to high-power, diode-pumped, thin-slab and 'thick' planar waveguide solid-state lasers where it offers the prospect of improved output beam quality, and hence higher brightness, as well as extended functionality compared to previous designs. A detailed study of the beam transformer and its application to planar devices will be conducted to establish resonator design criteria, the impact of thermal effects and the main limitations of the technique. The project will also explore several laser configurations (e.g. high-average-power CW and Q-switched lasers) aimed at demonstrating the key benefits to be derived via this approach. However, the main ambition of this work is to show that solid-state lasers based on a combination of planar active media and the beam transformer, can both rival and complement solid-state sources based on fibre and thin-disc technology, by offering the potential for high power and high brightness with added flexibility in mode of operation and a compact format, thereby meeting the needs of a range of applications.