ADJUSTABLE OPTICAL TEST APPARATUS INCLUDING INTERFEROMETER WITH MICROMIRROR AND ALIGNMENT OBSERVATION SYSTEM

摘要

An interferometer includes a beamsplitter for splitting a source beam into a test beamand a reference beam, an imaging device for detecting an interference pattern, a mirrordisposed in a path of the test beam for reflection of the test beam toward the imagingdevice, a micromirror disposed in a path of the reference beam for reflection of aportion of the reference beam toward the imaging device, and a focusing mechanismdisposed for focusing the reference beam on the micromirror. The micromirror has alateral dimension not exceeding the approximate lateral dimension of a central lobe ofthe reference beam focused thereon by the focusing mechanism. A spatial filter forreducing effects of aberration in a beam includes a reflector disposed upon a transpar-ent base wherein the reflector has a lateral dimension not exceeding the approximatelateral dimension of a central lobe of the spatial intensity distribution of the beamfocused upon the reflector. A method of filtering a beam in a wavefront measurementsystem is also provided. This method includes focusing the beam, reflecting aparticular first portion of the focused beam, and transmitting a second portion of thebeam.