Device for forming two beams for interferometer - has focusing system forming point source image on diffuser

摘要

The device produces two light beams, one of which is diffused and of uniform phase shift w.r.t. the other. It comprises a point light source, a diffuser not containing the light source, and a focusing system which forms the image of the source on the diffuser. The diffuser may be a partially polished piece of rough glass or a speckle plate obtained by photographing the light produced by illuminating a rough piece of glass with a laser beam.