Abstract

In recent years new methods for operating a lasei with a single high-order transverse mode have been reported (see review [1]). These methods based on the insertion of binary and spiral phasi elements within the laser resonator, resulted in higher output power with regard to the funda mental TEM₀₀ mode and improved beam quality with regard to multimode operation. It was alsc shown that the entropy of a single high-order mode is equal to that of a single Gaussian mode, so it is allowed thermodynamically to transform without losses a high-order mode beam into a Gaussian beam.² The high-order mode selection using these methods was demonstrated only in CW lasers, where low gain was present.

© 2002 Optical Society of America