High power waveguide lasers

During the past few years high power lasers which incorporate intracavity optical waveguiding have been demonstrated in a number of different geometric formats. These include rectangular planar waveguide structures, two-dimensional multielement waveguide array lasers and annular waveguide devices, all of which depend crucially on the operational flexibility of the transverse radiofrequency excitation technique. Here, we review the fundamental issues which underlie the attractions of the use of waveguiding structures in the design and construction of ultracompact, diffusion-cooled lasers which are efficient and operate at high average power levels. In particular, we review the properties of large area discharge planar waveguide CO2/CO lasers, where multi-kilowatt cw power levels have been demonstrated with excellent beam quality and efficiency. It is shown that similar concepts may also be applied to solid state lasers. In addition, the use of the multi-element array concept for high power scaling will be examined, and the operating characteristics of an ultra-compact 64 (4 x 16) element array laser operating at 2kW cw output power will be described.