Beam quality improvement by thermally induced aberrations in a diode-end-pumped laser amplifier

Beam quality improvement in a diode-end-pumped laser amplifier is realized theoretically and experimentally. The experimental and numerical results are in good agreement. A theoretical model of the laser oscillator and amplifier is developed by considering both thermal and gain guiding effects. With the decomposition of the wavefront aberration and thermally induced aberrations in terms of Zernike polynomials, the mechanism of beam quality improvement by thermally induced aberrations is investigated.