Abstract

It is well-known in magneto-optical (MO) recording that undesired readout beam ellipticity can be removed by using a quarter-wave plate or an adjustable compensator1. We will show that this ellipticity can be removed by any retardation plate, if its retardation magnitude is larger than the readout beam phase shift, or more precisely, if its retardation obeys the condition where δ is the phase shift between two orthogonal polarization components of the return beam along the carrier and MO signal polarization directions, and Δ is the retardation of the retardation plate. If the phase shift δ does not equal kπ, where k is an integer, then the return beam will be elliptically polarized. The carrier polarization direction is the polarization direction of a linearly polarized beam incident on a MO disk.

© 1996 Optical Society of America