Enhanced optical pumping of materials exhibiting polarization-dependent absorption

Abstract

An optically pumped laser oscillator or amplifier includes a laser head having a gain medium exhibiting polarization-dependent absorption along two crystallographic axes and a pump source producing a pump beam. The medium's absorption coefficients along both said crystallographic axes are equal or the difference between the absorption coefficients relative to the lowest absorption coefficients R=Abs(α−α)/(min(α, α)) is reduced at least by a factor of two compared to the same relative difference between the two absorption coefficients at the medium's absorption peaks, used for conventional pumping by pumping with unpolarized or partially polarized pump light at a wavelength around which the average absorption coefficients along both of said crystallographic axes are equal or present a relative difference that is reduced by a factor of two or better compared to conventional pumping around the medium's absorption peaks.