Laser beam brightness of apertured optical resonators

We model the fundamental mode of a circularly symmetric plano-concave resonator where one mirror is apertured by a super-Gaussian aperture, while the other is apertured by a π/2 phase aperture. The aim of the paper is to find the best values of the apertured cavity parameters allowing the highest output beam brightness. For that we take into account loss level, fundamental mode volume and beam quality factor M2. We demonstrate that for a given loss level, the phase aperture is able to increase the laser beam brightness, with a rate of about 60% when its diameter is properly chosen.