Abstract

Planar waveguide geometry provides a method of scaling the power of lasers in proportion to active area, and is used in both gas lasers, using hollow guides,¹ and broad area index guided semiconductor lasers.² For example, RF excited CO₂ lasers using a slab waveguide cavity produce a specific output power in the range 20-30 kW·m^-2.¹ These devices are characterised by an output consisting of multiple lateral waveguide modes¹-² unless methods are used to ensure single frequency operation.^1,3 In this paper, a new technique is presented in which mode selecting longitudinal grooves are cut into the electrodes of the slab waveguide CO₂ laser, as shown in Fig. 1. The structure consists of two ceramic side walls of length 386 mm, sandwiched between water cooled aluminium electrodes.

© 1994 Optical Society of America