Patent ID: 6819844
Filing Date: 2004-11-16
Classification: G01N

Abstract:
A fiber-based nonlinear optical system for performing surface-sensitive spectroscopic characterizations on a surface to be interrogated, comprising:a) a first optical source for providing a first input, said first optical source comprising a fixed wavelength laser; b) a first input optical fiber for receiving said first input and transmitting said first input to a first position proximate a location on a surface to be interrogated; c) first input fiber coupling optics for receiving said first input from an output end of said first input optical fiber and delivering said first input to the interrogated location on the surface; d) a second optical source for providing a second input, said second optical source comprising a tunable wavelength laser; e) a second input optical fiber for receiving said second input and transmitting said second input to a second position proximate the interrogated location; f) second input fiber coupling optics for receiving said second input from an output end of said second input optical fiber and delivering said second input to the interrogated location on the surface, said first and second inputs being aligned so that their surface locations of optical illumination overlap on said interrogated location; g) output fiber coupling optics for receiving a reflected output resulting from a nonlinear three-wave mixing process of said first and second inputs being aligned so that their surface locations of optical illumination overlap on said interrogated location, said nonlinear three-wave mixing process comprising sum-frequency generation end difference frequency generation occurring at said interrogated location, wherein: said output fiber coupling optics are positioned between the reflection of said first input from the surface and the reflection of said second input from the surface for a sum-frequency output propagation direction and said output fiber coupling optics are positioned below both the reflection of said first input from the surface and the reflection of said second input from the surface for a difference-frequency output propagation direction; h) an output optical fiber for receiving an output of said output fiber coupling optics and transmitting the output to a desired third position from said interrogated location; and i) an output sensor system for receiving an output of said output optical fiber and collecting, analyzing and interpreting said output of said output optical fiber, wherein said first and second optical sources end said output sensor system may be disposed at desired distances and angles from said interrogated location.