Performance and Quality Characterization of the Reference MNA Nonlinear Optical Molecular Crystal by Pockels Electrooptic Confocal Microscopy

The recently proposed Pockels linear electrooptical microscopy is being applied to a quality and performance characterization of the 2‐methyl‐4‐nitroaniline quadratic nonlinear optical molecular crystal down to confocal microscope resolution. Samples are grown between electrodes in single‐film format. The dominant electrooptic tensor coefficient is determined and the distribution of the electric field is mapped so as to characterize polycrystalline features. The Pockels polarization response is shown to provide a unique way to the unambiguous assignment of the principal dielectric axis in the case of a low symmetry crystal. Application toward weak electric‐field sensing at a local scale is demonstrated.