Patent ID: 8436997
Filing Date: 2013-05-07
Classification: G01B,G01J,G01N

Abstract:
1. An optical system, comprising: an illumination subsystem for providing a source of coherent light; a first optical detector for detecting light reflected from a surface under inspection; and a polarizing isolator for polarizing the coherent light provided by the illumination subsystem and directing resulting polarized light having a first polarization state along an illumination optical path to generate a spot on the surface under inspection, wherein the polarizing isolator further couples the reflected light returning along the illumination optical path to the first optical detector along a detection optical path directed away from the illumination subsystem and wherein the polarizing isolator further comprises a second polarizing element that directs reflections from the detection optical path to an isolated optical path away from the illumination optical path, whereby light reflected from structures along the detection optical path is prevented from re-entering the illumination optical path.