Patent ID: 9599454
Date: 2017-03-21
CPC Classifications: G01B,G01J,G01N

Claim:
1. An optical interferometer comprising: a light source that emits a coherent pump beam with a first optical frequency and emits a Stokes beam with a second optical frequency that has, with respect to the first optical frequency, a frequency difference corresponding to a natural frequency of a target molecule; an amplitude modulating unit that applies a periodic amplitude modulation at a third frequency to the Stokes beam; a splitting unit that splits the pump beam into a reference beam and an applied pump beam; a frequency modulating unit that applies a frequency modulation at a fourth frequency to the reference beam; an optical path length adjusting unit that adjusts the optical path length of the reference beam; and a detecting unit into which is inputted (i) an applied Stokes beam, which is the Stokes beam to which the periodic amplitude modulation has been applied, and (ii) a signal beam, which is the applied pump beam following a stimulated Raman loss or a stimulated Raman gain in accordance with the periodic amplitude modulation of the applied Stokes beam as a result of the frequency difference between the applied pump beam and the applied Stokes beam resonating with the target molecule when the applied pump beam and the applied Stokes beam have been applied to a measurement position of an object, and wherein the detecting unit detects a heterodyne interference pattern between the signal beam and the reference beam to which the frequency modulation has been applied.