Dynamic change detecting method, dynamic change detecting apparatus and ultrasonic diagnostic apparatus

摘要

A dynamic change detecting apparatus allows canceling the influence of environmental change or an individual difference between a plurality of laser elements so as to perform a stable detection. This apparatus has a laser, including a laser resonator, for emitting a laser beam while causing frequency modulation in accordance with dimensional change of the laser resonator; a partial reflection mirror for splitting the laser beam emitted by the laser into a plurality of split-beams and guiding the plurality of split-beams to a plurality of optical paths having mutually different optical path lengths respectively; a frequency shifter for causing frequency shift in at least one of the plurality of split-beams; a lens for combining the plurality of split-beams with each other to obtain interference light; an photodetector for detecting the interference light to obtain an intensity signal; a demodulation unit for demodulating the intensity signal to generate a demodulated signal; and an integration processing unit for obtaining a signal corresponding to the dynamic change on the basis of the demodulated signal.