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. © The Institution of Engineering and Technology 2014.