Defects in ellipsometer elements are treated in first order in a general formalism that expresses the null conditions of an ellipsometer or simpler system as a series of simultaneous linear equations. The solution of these equations is used to develop experimental procedures for the detection and measurement of these defect parameters, and to determine the effect of these parameters on ellipsometrically determined quantities. Defects that can be detected in first order include leakage and scattering in the polarizing prisms and scattering and strain birefringence in the compensator. Defects that can be detected and measured in first order include birefringence in the polarizing prisms and associated modulation cells, optical activity in the compensator, cell-window birefringence, and sample-surface quality. The experimental procedures also determine the absolute reference-azimuth angles of the polarizer and analyzer prisms and the compensator. Experimental results illustrating various aspects of the theory are presented.
D. E. ASPNES, "Measurement and Correction of First-Order Errors in Ellipsometry," J. Opt. Soc. Am. 61, 1077-1085 (1971)