Abstract

RF-excited CO₂ slab-waveguide lasers are particularly convenient vehicles for exploratory experiments with diffractive- optic resonators. They have very large Fresnel numbers in the lateral direction, and support low-order waveguide modes in the transverse direction. This permits the use of a one-dimensional diffractive optical element (DOE) inside the resonator, which may be designed to produce a novel approach to output coupling, without the need for a transmissive mirror. In the simplest resonator configuration, a slab-waveguide structure was used with plane/plane mirrors, one of which incorporated a reflective DOE and acted as a one-dimensional diffractive Fresnel mirror. The slab-waveguide structure was designed such that reflecting side walls, confining the radiation in the lateral direction and giving rise to lateral waveguide modes,¹ could be removed for certain experiments, so that radiation propagated without confinement in the lateral direction.

© 1996 Optical Society of America