US Patent 7894500 Non-linear waveguided laser channel for a gas laser

An RF-excited waveguide laser module comprises a first electrode having a first elongate surface defining in part a waveguide laser channel extending along an optical axis, the first elongate surface having a substantially linear cross-section normal to the optical axis. A second electrode has a second elongate surface defining in part the waveguide laser channel extending along the optical axis. The second elongate surface has a non-linear cross-section normal to the optical axis. A dielectric insert may be provided between the electrodes defining in part the waveguide laser channel. A lengthwise gap may extend essentially an entire length of the waveguide laser channel between one of the first and second electrodes and the dielectric insert. The gap provides fluid communication between the waveguide laser channel and a volume outside the waveguide laser channel.