Axial dependence of optical weak measurements in the critical region

The interference between optical beams of different polarizations plays a fundamental role in reproducing the optical analog of the electron spin weak measurement. The extraordinary point in optical weak measurements is represented by the possibility of estimating with great accuracy the Goos-Hanchen (GH) shift by measuring the distance between the peaks of the outgoing beams for two opposite rotation angles of the polarizers located before and after the dielectric block. Starting from the numerical calculation of the GH shift, which clearly shows a frequency crossover for incidence near the critical angle, we present a detailed study of the interference between s and p polarized waves in the critical region. This makes it possible to determine in which conditions axial deformations can be avoided and the GH curves reproduced. In view of a possible experimental implementation, we give the expected weak measurement curves for Gaussian lasers of different beam waist sizes propagating through borosilicate (BK7) and fused silica dielectric blocks.