Patent Document ID: 5477324
Application ID: 08296541
Patent Flag: 1

Claim One:
1. A method of detecting and specifying resolved vector dynamics on the surface of a vibrating object, said method comprising the steps of: (a) directing a first beam of coherent light having an optical frequency f1 onto the surface at a point P along a path that forms a first predetermined angle with respect to a normal to the surface at the point P; (b) directing a second beam of coherent light having an optical frequency f2 onto the surface at the point P along a path that forms a second predetermined angle with respect to the normal to the surface at the point P, said second predetermined angle being substantially equal to said first predetermined angle so that said first and said second beams of coherent light traverse paths that are symmetrically oriented about the normal to the surface at point P; (c) directing a third beam of coherent light having an optical frequency f3 onto the surface at the point P along a path that forms a third predetermined angle with respect the normal to the surface at point P, said third predetermined angle being substantially different from said first and said second predetermined angles so that said third beam of coherent light traverses a path that is asymmetrically oriented about the normal with respect to said first beam and with respect to said second beam; (d) said light beams combining on the surface at point P with the resulting light scattered from the surface being a superposition of said first, second, and third light beams and exhibiting carrier signals due to interference at frequencies approximately equal to the difference between the optical frequency of each beam and the optical frequency of each of the other beams, said carrier signals being frequency modulated by vibrational motion of the surface of the object; (e) detecting the superimposed scattered light from point P on the surface; (f) analyzing the detected light at the frequencies of at least one of the carrier signals to extract modulation characteristics therefrom; and (g) converting the extracted modulation characteristics to vibrational vector dynamics of the surface that induced the modulation of the analyzed carrier signals.