Waveguide laser having a capacitively coupled discharge

An optical apparatus comprising:

• an optical resonant cavity bounded by first and second mirrors, said mirrors disposed along an axis extending through said cavity;
• a dielectric waveguide having an outside surface and a capillary bore disposed along said axis within said cavity for guiding radiation within said capillary bore;
• a gaseous optical gain medium disposed within said waveguide;
• energizing means for creating a population inversion by capacitive coupling within said gain medium, whereby optical radiation is resonated between said mirrors and guided by said waveguide;
• wherein the improvement comprises that said energizing means for creating a population inversion includes an electrode structure comprising a first electrode disposed outside said waveguide and a second electrode having an active end disposed within said gaseous gain medium and further improved in that said energizing means includes means for applying a voltage pulse between said first and second electrodes, whereby said population inversion is created in said gain medium by coupling energy from said electrodes to said gain medium.