Null ellipsometry is analyzed for components with depolarizations for unpolarized incident light. Serious imperfections include sample depolarization D < 0.2, misalignment (δ<i>C</i> < 2°) and off-quarter-wave retardance (δτ < 5°) of the compensator. The four-zone null positions are derived analytically to the second order of serious imperfections and are also simulated based on Mueller matrices with depolarization. Errors of all four-zone nulls increase with increasing D. Depolarizations of all components except the analyzer cause errors to the nulls. The errors associated with D always couple with the second order of δ<i>C</i> and δτ and are enhanced by csc<sup>2</sup> 2ψ. These divergent errors limit the applicable region of null ellipsometry where the errors in ψ and Δ are within 0.1°, and the simulation agrees well with the analytic solutions.
© 1999 Optical Society of America
Soe-Mie F. Nee, "Error Analysis of Null Ellipsometry with Depolarization," Appl. Opt. 38, 5388-5398 (1999)