Automatic Whole-Field Measurement of Total Relative Phase Retardation using Three Wavelengths

Abstract

The automatic measurement of the total relative phase retardation (ρ_itol) of a photoelastic model is performed in the whole field by using the linearly polarized light at three different wavelengths of monochromatic light. The relative phase retardation (ρ_i) at each wavelength λ_i is obtained from Stokes parameters without the influence of the isoclinic angle. The measurement range of the model can be more widely taken compared with a two-wavelength method. The ρ_itol was calculated by the coincident method using ρ₁, ρ₂ and ρ₃. In the experiment of the circular disk under compression, the ρ_itol in the rang 0-5π agreed well with the theoretical values.