Off-axis parabolic mirrors: A method of adjusting them and of measuring and correcting their aberrations

Abstract

This paper proposes a method of adjusting off-axis parabolic mirrors, based on the minimization of beam-quality parameter M². This method requires no additional adjustment elements and possesses adequate accuracy: 1% for the angular orientation of the mirror and 2.3% for the rms deviation of the M² value. An experimental technique is given for measuring and correcting the aberrations of strongly focusing off-axis optical elements. The technique is based on measuring the wave front by the Shack-Hartmann method. The aberrations were corrected using a controllable flexible mirror in the manual and automatic regimes by the aperture-probing and phase-conjugation methods, respectively. © 2005 Optical Society of America