Brightness enhancement of solid state laser oscillators in single-mode lasing using novel inside-resonator optical elements with radially variable transmission

摘要

The results of intracavity application of soft or apodized apertures (AA) with smooth transmission profiles decreasing from the center to the edges are presented. Photooxidation (PhO) AA, made of CaF$-2$/:Pr crystals were used. The approximately 3-4 mm diameter of PhO AA with bell-like transmission profiles as placed inside the 2.94 $mu@m and 1.06 $mu@m resonators of master oscillators. The tendency of the order of magnitude of 1.3 - 1.8 times increasing in output energy and diminishing in beam divergence in single-mode lasing as compared with hard-edge aperture have been observed in the experiment described.