NANOMETER-SCALE POLARIMETRY STUDIES USING A NEAR-FIELD SCANNING OPTICAL MICROSCOPE

We describe a new technique that incorporates polarization modulation into near-field scanning optical microscopy (NSOM) for nanometer scale polarimetry studies. By using this technique, we can quantitatively m easure the optical anisotropy of materials with both the high sensitiv ity of dynamic polarimetry and the high spatial resolution of NSOM. Th e magnitude and relative orientation of linear birefringence or linear dichroism are obtained simultaneously. To demonstrate the sensitivity and resolution of the microscope, vee map out stress-induced birefrin gence associated with submicrometer defects at the fusion boundaries o f SrTiO3 bicrystals, Features as small as 150 nm were imaged with a re tardance sensitivity of similar to 3 x 10(-3) rad. (C) 1998 Optical So ciety of America.