Improvement of spatial beam quality of laser sources with an intracavity Bragg grating

摘要

We demonstrate a novel method for improvement of spatial beam quality by using the angular selectivity of a thick phase grating inserted in different laser cavities. Preliminary experiments with a voluntary degraded beam from a Nd:YVO_4 laser have enhanced the beam propagation factor M~2 by a factor of 4.5. Operation with a broad area laser diode in an external cavity with a thick grating was achieved. We obtained 100 mW of cw power in a beam with a M~2 of 1.3. Moreover a reduction by a factor up to 3.8 of the output spectrum was obtained.