Computer studies have shown that azimuthal static mirror misfigures as small as λ/20 can lead to severe degradation in the far field on axis intensity for resonators with an annular gain region. This poor far-field pattern can, however, be dramatically improved by the use of adaptive elements within the resonator. A rear cone in the resonator had a static misfigure applied to it, and an adaptive ring axicon located in the front of the resonator was deformed in such a way as to compensate for the misfigure of the rear element of the resonator.
© 1980 Optical Society of America
J. B. Shellan, D. A. Holmes, M. L. Bernabe, and A. M. Simonoff, "Adaptive mirror effects on the performance of annular resonators," Appl. Opt. 19, 610-615 (1980)