A grating based curvature sensor

摘要

Curvature sensing is a technique that provides the phase of wavefronts through measurements of irradiance in well defined planes along a beam of light. The equation describing the propagation of intensity and phase is well known; here the profile of a collimated monochromatic beam is determined at a certain longitudinal position by measuring the irradiance pattern at two planes either side of that position. Using a distorted grating lens, the intensity profiles of the two planes can be recorded simultaneously. Their difference may be related back to the wavefront phase either through solutions of the Intensity Transport Equation. The theory and first experimental results are reported.