Abstract

The traditional solid-state phase-retardation plate can only be used as either a quarter- or half-wave plate for each given thickness and wavelength. Babinet’s compensator, which consists of two wedges of quartz with equal acute angles, can provide tunable birefringence by displacing these two wedges and forming a parallel plate of variable thickness. However, this suffers some disadvantages: (1) spatial nonuniformity—each portion of the beam width, in principle, experiences different phase retardation; (2) calibration—the output polarization is not easy to calibrate over a wide wavelength range; and (3) beam deviation—the outgoing beam may be deviated by any mechanical displacement.

© 1984 Optical Society of America