Abstract

The difficulty of measuring optical phase has long presented an obstacle to optical aperture synthesis with interferometers. This difficulty is very easily overcome by using an ordinary lenticular screen as a three-phase interferometer that permits counting essentially all of the incident photons, offers wide bandwidth, and has no moving parts. The particular screen used in our experiments has 40 lenticular grooves per mm. Three neighboring photodetectors then give signals that may be combined to eliminate the common-mode while making available simultaneous in-phase and quadrature fringe signals; the same as are routinely acquired in radio interferometry. Careful rejection of the common-mode allows legitimate static operation with low-contrast fringes and with no need for scanning or a.c. coupling.

© 1983 Optical Society of America