Abstract

CO₂ waveguide lasers are usually designed with a view to obtaining operation exclusively on the lowest order resonator mode (often closely similar to the fundamental EH₁₁ waveguide mode). However, this is not always achieved in practice because of various factors including the complications resulting from the incorporation of several intracavity elements and mirror misalignments. Higher-order resonator modes may come above threshold resulting in the mode-beating behaviour often referred to as hooting? For applications requiring single-frequency operation, such as coherent lidar, this is undesirable.

© 1994 IEEE