We describe the use of an asymmetric feedback ring in an unstable resonator to obtain arbitrarily narrow-linewidth radiation across the full available aperture. We demonstrate its use with an electric-discharge XeCl laser to produce single-line radiation with a linewidth of 0.15 cm−1.
© 1988 Optical Society of America
Original Manuscript: January 11, 1988
Manuscript Accepted: April 7, 1988
Published: July 1, 1988
D. Cooper, L. L. Tankersley, and J. Reintjes, "Narrow-linewidth unstable resonator," Opt. Lett. 13, 568-570 (1988)