HOLOGRAM INTERFEROMETER FOR MEASURING SURFACE SHAPE OF LARGE-APERTURE PLANE MIRROR

摘要

PURPOSE:To enable measurement of the surface shape of a large-aperture plane mirror by providing a hologram interference system having an optical system for reference light and an optical system for illuminating light and observing the interference fringe between the reconstructed object light reconstructed by a hologram and the illuminating light. CONSTITUTION:A hologram interferometer 1 is constituted of a laser light source 3, the optical system 4 for reference light provided with a reflection mirror M1, a microscopic objective lens MO1 and a pinhole P1 and a hologram HP and the optical system 6 for illuminating light provided with reflection mirror M3, a microscopic objective lens MO3 and a pinhole P3. The set position of the plane mirror MM to be inspected is set as specified. The parallel light from the laser light source 3 is split by a beam splitter BS1. One of the luminous fluxes is made incident on the hologram HP via the system 4 and the object light is reconstructed. The other luminous flux is passed through the system 6 to form the illuminating light which is reflected by the mirror surface MM and is then made incident on the hologram HP then the interference fringe is generated by the reconstructed object light and the reference light and therefore the measurement of the surface shape is made possible.