Patent ID: 6594290
Filing Date: 2003-07-15
Classification: G01H,G01N

Abstract:
A dynamic change detecting method comprising the steps of:(a) emitting a laser beam while causing frequency modulation to the laser beam to be generated in accordance with change in a size of a laser resonator by propagating the dynamic change to a total reflection mirror included in the laser resonator to cause dynamic perturbation to said total reflection mirror; (b) separating the laser beam into a plurality of split-beams and guiding said plurality of split-beams to a plurality of optical paths having mutually different optical path lengths, respectively; (c) causing frequency shift in at least one of said plurality of split-beams; (d) combining said plurality of split-beams with each other to obtain interference light; (e) detecting said interference light to obtain an intensity signal corresponding to intensity of the interference light; (f) demodulating the intensity signal to generate a signal corresponding to the dynamic change.