Haike GUAN, Masahiro YAMAGUCHI, Nagaaki OHYAMA and Toshio HONDA

Imaging Science and Engineering Laboratory, Tokyo Institute of Technology, 4259, Nagatsuta, Midori-ku, Yokohama, 227 Japan

(Received June 24, 1994; Accepted September 5, 1994)

A new CGH (computer generated hologram) common path interferometer, which can be used for testing an aspherical mirror with large aperture, is proposed. This interferometer does not have a circle of least confusion, and a spatial filter can be used effectively to stop extraneous lights so that interferograms with good contrast can be obtained. The phase shifting technique can be easily applied to the interferometer. The method of designing and making the CGH zone-plate is described.

Key words : aspherical mirror, large aperture, common path interferometer, caustic waist, computer generated hologram, diffraction efficiency balance, laser writer, phase shifting