Patent ID: 6493091
Filing Date: 2002-12-10
Classification: G01B,G01N

Abstract:
An interference detecting apparatus, comprising:a light source emitting light having coherency; a first signal generating means generating a first signal having a frequency of f1; a first optical frequency comb generating means using the first signal provided from said first signal generating means, and modulating the light provided from said light source, so as to generate reference light having a sideband every interval of frequency f1 in the light provided from said light source; a second signal generating means generating a second signal having a frequency of f2; a second optical frequency comb generating means using the second signal provided from said second signal generating means, and modulating the light provided from said light source, so as to generate object light having a sideband every interval of frequency f2 in the light provided from said light source; a combining means combining the reference light provided from said first optical frequency comb generating means and the object light generated by said second optical frequency comb generating means and reflected by a to-be-measured object so as to generate interference light; and a detecting means controlling interference timing between the reference light provided from said first optical frequency comb generating means and the object light provided from said second optical frequency comb generating means, by using a phase difference or frequency difference between the first signal and second signal, and detecting a change in light intensity of the interference light.