Patent ID: 7304722

Claim:
An apparatus for analyzing an object comprising: a laser generating an initial pump beam; a first nonlinear crystal receiving said initial pump beam and generating a second pump beam and first and second primary Spontaneous Parametric Downconversion (SPDC) beams; a second nonlinear crystal receiving said second pump beam and generating first and second secondary SPDC beams; polarizing means for adjusting a phase angle of at least some of said primary and secondary SPDC beams; first combining means for combining the first primary SPDC beam with the first secondary SPDC beam to form first coincident SPDC beams; second combining means for combining the second primary beam with the second secondary beam to form second coincident SPDC beams; means for directing the first coincident SPDC beams at an article; and means for analyzing Raman backscattering associated with the impingement of said first SPDC beams on said article to derive a predetermined characteristic of said article.