High-power TEM00 and Laguerre-Gaussian mode generation in double resonator configuration

A simple method for controlling the spatial gain distribution in an end-pumped solid-state laser to allow the selective excitation of the fundamental Gaussian (TEM00) and the first-order Laguerre-Gaussian doughnut (LG(01)) modes is reported. This approach has been applied to a Nd:YAG laser yielding 2.21 W of the TEM00 mode output and 1.62 W of the LG(01) mode output at 1064 nm for 7.36 W of incident pump power at 808 nm. The corresponding slope efficiencies with respect to incident pump power were 40 and 32 % for the TEM00 and LG(01) modes, respectively. The underlying mechanism and the prospects for further improvement in laser performance are discussed.