ENHANCEMENT OF THE UNIFORMITY AND ROTATION OF LARGE-APERTURE, PERMANENT-MAGNET, TUNABLE FARADAY ROTATORS

We present new methods for increasing the magnitude and uniformity of rotation of a Faraday rotator with a large clear aperture. We show the oretically and experimentally that the amount of rotation and the unif ormity of rotation across the aperture can be simultaneously increased by introducing a small separation between adjacent, oppositely orient ed magnets. Furthermore we show that the uniformity can be increased b y displacing the rod of rotator glass longitudinally from the centred position. We have constructed such a device and obtained an isolation ratio of 45 dB at 1.06 mu m.