Ellipsometric measurements and its alignment: Using the intensity ratio technique

Using first-order treatment on azimuth errors of the polarizer (P) and analyzer (A) with respect to the plane of incidence (POI), we construct two intensity ratios around a certain configuration, such as P= ±п/4 and A = 0 as compared to A = п/2. These expressions can be used not only to align the azimuths of the polarizer and analyzer to the POI, but also to obtain the ellipsometric parameter Ψ without locating the minimum intensity. BK7 glass and Si02/Si thin film are ultilized to evaluate this technique.