Experimental investigation of laser beam diffraction on phase step and its practical applications

The change in shape of the spatial spectrum, which is a result of the interaction of a focused laser beam with a phase step structure (PSS), is investigated. As a laser beam passes through a PSS, a spatial spectrum of radiation in the form of two peaks with a deep gap in between is generated. The change in the peaks´ structure as the PSS moves relative to the optical axis of the laser beam is studied in detail. On the basis of the experimental results, a new scheme for measuring small linear and angular deviations is proposed.