Method and Apparatus for Measuring Near-Angle Scattering of Mirror Coatings

McClain, Stephen C. ; Daugherty, Brian J. ; Macenka, Steven A. ; Chipman, Russell A.

PID  :  NTRS Document ID: 20140016610

学科分类：原子、分子光学和等离子物理

美国|英语

来源: NASA Technical Reports Server

【 摘 要 】

Disclosed herein is a method of determining the near angle scattering of a sample reflective surface comprising the steps of: a) splitting a beam of light having a coherence length of greater than or equal to about 2 meters into a sample beam and a reference beam; b) frequency shifting both the sample beam and the reference beam to produce a fixed beat frequency between the sample beam and the reference beam; c) directing the sample beam through a focusing lens and onto the sample reflective surface, d) reflecting the sample beam from the sample reflective surface through a detection restriction disposed on a movable stage; e) recombining the sample beam with the reference beam to form a recombined beam, followed by f) directing the recombined beam to a detector and performing heterodyne analysis on the recombined beam to measure the near-angle scattering of the sample reflective surface, wherein the position of the detection restriction relative to the sample beam is varied to occlude at least a portion of the sample beam to measure the near-angle scattering of the sample reflective surface. An apparatus according to the above method is also disclosed.