Risley prisms systems consist of two-wedge aligned prisms that deviate a light beam or wavefront. The relative angle between prisms determines the displacement of the central point wavefront. In the case of wavefront propagation through the Risley system, the relative angle also can introduce a controlled tilt. Then, the beam’s or wavefront displacement direction is controlled by changing the relative angle between prisms. Risley prisms have been used in multiple applications such as super-resolution imaging and field of view (FOV) extension, steering systems, precision pointers, scanning systems, and wavefront alignment and positioning. This paper presents a description of the techniques used by Risley prisms making a compilation of their most essential characteristics. One of the related applications is reviewed on a Vectorial Shearing Interferometer. The paper overviews the advantages and disadvantages of using Risley prisms in different valuable applications.
|