Diffraction experiments with the spatial light modulator: the boundary between physical and digital optics

摘要

A spatial light modulator is a matrix-shaped device able to modify the amplitude or the phase of the reflected or transmitted light, which can be operated pixel by pixel independently. This opens new possibilities for rapid and efficient manipulation of the light diffraction but also brings us close to the ambiguous boundary between physical and digital optics, or more precisely between the continuous and the discrete mathematical approaches of diffraction. In this article we show a series of diffraction experiments in which we use the modulator to simulate various optical elements, physically real or not, recorded real or computed holograms, experiments in which due to the discrete nature of the modulator we are liable to use alternately the discrete and the continuous approach. To avoid ambiguities we have to keep track of the approaches we use, and also, more importantly, to be able to switch from discrete to continuous terms and vice-versa.