Roughness measurement by optical vortices array with nanoscale

Abstract

In present report, we review the principles and applications of interference vortex method for the real time determination of polished surface roughness for transparent and reflecting materials with using of Laguerre-Gaussian probe beam array of low index as well as a reference beam. High spatial resolution caused by interference of vortices and their phase sensitivity, which is automatically analysable to retrieve the 2D and 3D shape of micro- and nanostructured surfaces with exceeding of optical diffraction limit which is applicable for non-destructive testing of roughness analysis of thin films and solid microstructures in real-time regime with longitudinal and transverse resolution down to 1.75 nm and 7 nm respectively for visible light sources. The dependence of the angle of rotation of the resulting interference pattern on the optical path difference and sample thickness for two singular beams superposition is considered in detail.