METHOD AND APPARATUS FOR THE TWO-DIMENSIONAL MAPPING OF THE ELECTRO-OPTICAL COEFFICIENT

摘要

A method for measuring and two-dimensional mapping of electro-optical properties of materials using a Reflective Grating Interferometer (RGI) includes projecting a substantially coherent and monochromatic electromagnetic beam subjected to a homogeneous electrical field so the beam is enlarged to have a two-dimensional cross section comparable with dimensions of the material, dividing the electromagnetic beam into one part that crosses the material and another part that travels undisturbed, recomposing the two beams on a recombination element of the RGI, detecting the recombined beam by a device suited to two-dimensional detection of such beam. The method also includes: E. obtaining phase variation Deltaø(x,y) between the divided beams; F. varying the applied electrical field value and repeating the detection steps; G. calculating properties using: $\mathrm{Delta}\mathrm{Phi}\left(x,y\right)=\left(\frac{\mathrm{pi}}{\mathrm{lambda}}\right).\left[-n_0^3\left(x,y\right).r_{13}^{\text{'}}\left(x,y\right).V\right]$ where DeltaPhi=phase difference, V=value of the voltage difference, r'₁₃=electro-optical parameter, and n₀=ordinary refraction index. A corresponding apparatus is also described.