Experimental performance of several different unstable resonators with annual cylindrical mode volumes is reported. Laser output beam quality and its sensitivity to resonator component misalignments and figure errors are described. Near diffraction-limited beam quality was obtained from an annular cylindrical He-Xe laser employing a half-symmetric unstable resonator with an intracavity axicon.
© 1978 Optical Society of America
P. B. Mumola, H. J. Robertson, G. N. Steinberg, J. L. Kreuzer, and A. W. McCullough, "Unstable resonators for annular gain volume lasers," Appl. Opt. 17, 936-943 (1978)