title: Experimental investigation of saturable gain-guided modes.
abstract: Hermite-Gaussian modes in geometrically unconfined resonators with a four-level system saturable gain guide inside are experimentally observed and proved. The gain guide was formed with a polished cylindrical surface low-concentration Nd:YAG rod exposed to isotropic pump radiation. The connection of the mode scaling factor with the system parameters is compared with the theory. The abilities of the recently established gain-saturation guiding mechanism to support the generation of beams with wide tops and rapidly decreasing intensity in the wings are also experimentally proved. Application areas for saturable gain guiding are briefly discussed.
authors.affiliation: Department of Quantum Electronics, Faculty of Physics, Sofia University, 33A Galichitsa Street, BG 1164 Sofia, Bulgaria. odenchev@phys.uni-sofia.bg
authors.forename: Ognian
authors.initials: O
authors.lastname: Denchev
authors.forename: Stoyan
authors.initials: S
authors.lastname: Kurtev
authors.forename: Plamen
authors.initials: P
authors.lastname: Petrov