Patent ID: 7214932
Filing Date: 2007-05-08
Classification: G01N

Abstract:
1. An optical system, comprising: an illumination system for providing an illumination beam for illuminating a surface of interest through a first partially reflective surface; at least one reflector including said first partially reflective surface for sustaining multiple internal reflections in a resonant cavity formed at least partially between said at least one reflector and said surface of interest, and wherein an extraction partially-reflective one of said at least one reflector permits light to exit said resonant cavity; a detector for detecting an intensity of light leaving said cavity through said extraction reflector; a scanning system for moving one of said illumination beam and said surface of interest to generate a relative movement between said surface of interest and said illumination beam; and a processing system having an input coupled to said detector for identifying at least one material type of an artifact disposed at said surface of interest from a change in a resonance position and amplitude of said detected intensity caused by said relative movement across said artifact.