Abstract

Conical lenses, often named axicons, produce a smooth focus which is highly suited for optical pumping of infrared lasers. The combination of a converging and a diverging axicon geometrically isolates the pump beam from the infrared laser cavity. We have used this geometry to pump the 12.1-and 12.8-µm lines of an NH₃ laser with a low-power TEA CO₂ laser; conversion efficiency is improved compared to previous studies done at the same power level with other geometries. We present the results obtained with a high-power (5-J) single-mode TEA CO₂ pump beam. A proposal for an optically pumped, unidirectional ring laser based on the axicon geometry is also discussed.

© 1985 Optical Society of America