An Automatic Retardation Meter for Automatic Polarimetry by Means of an ADP Polarization Modulator

Abstract

The construction of a new automatic retardation meter with an ADP polarization modulator and some results obtained with the apparatus are reported. An ADP solid Kerr cell which is subjected to an alternating voltage is inserted in an optical system which measures birefringence, and the retardation of a test piece is modulated. The modulated signal is amplified and fed to a servomotor, which controls the retardation compensation to get extinction. The retardation of the test piece is obtained from the amount of compensation. A practical apparatus, which is suited to study the characteristics of fibers, is made, and the effects of heat treatment and recrystallization of some synthetic fibers are measured.