Abstract

Large Fresnel number laser resonators necessitate confined or not confined telescopic cavity configurations to achieve a large fundamental mode volume. However, telescopic cavities using diffractive output coupling, i.e., unstable confined resonators, exhibit doughnut-type near-field modes with unwanted energy in far-field rings. Furthermore, high magnification M is required to obtain a single transverse mode. It has been established¹ that resonators with Gaussian reflectors have a nonunity magnification M defined as the ratio of the spot size incident on the Gaussian reflector to that existing after the reflector itself. The spot sizes in this case are given by the complex ABCD matrix analysis.

© 1985 Optical Society of America