Four-measurement technique for elimination of errors in phase plates calibration

摘要

In previous works, it was shown that two phase plates could be calibrated simultaneously in the optical system P-C{sub}1-C{sub}2-A where P, A are two polarizing prisms and d, C{sub}2 are the calibrated plates set with their fast axes at 45° and 0° respectively. Mathematical expressions for the system at different settings of the two plates are derived in this work and it is shown that systematic errors in the initial settings of the four involved optical elements P, C{sub}1, C{sub}2 and A could be eliminated by considering measurements at four definite settings of the two plates. At the same time, random errors of different sources are highly eliminated. Experimental results for two mica plates of thicknesses 39.8 μm and 28.7 μm are presented.