Generation of super-Gaussian modes in Nd:YAG lasers with graded-phase mirrors

摘要

To change the intensity distribution of the fundamental mode in a Nd: YAG laser resonator to a top-hat profile we developed and used a dielectric graded-phase mirror. A super-Gaussian mode of the sixth order was generated by means of a graded-phase mirror with a simple ring-shaped phase step on a spherical reflector. The depch of the ring was 90 nm. The graded-phase mirror was manufactured with an ordinary vapour deposition technique. An annular mask with a thickness of 10 μm was used to avoid the deposition of the LaF_3 vapour at the position of the ring. Laser experiments with continuous-wave and repetitively pulsed diode-laser pumping were performed and compared. The results are in excellent agreement with the theory.