ULTRASONIC MEASUREMENT DEVICE FOR REALIZING DIFFERENTIAL BALANCE DETECTION ON BASIS OF SAGNAC PRINCIPLE

摘要

Disclosed is an ultrasonic measurement device for realizing differential balance detection on the basis of the SAGNAC principle, the ultrasonic measurement device comprising a light source, a first polarization controller, a second polarization controller, a first non-polarization 1*2 coupler, a second non-polarization 1*2 coupler, a sample probe, a circulator, a polarization beam splitter and a balance detector. Light emitted from the light source first passes through the first polarization controller and the circulator, and is divided into two paths with different lengths via the first non-polarization coupler, with one path being CW light in the clockwise direction, and the other path being CCW light in the anticlockwise direction; and by controlling the included angle between slow axes of the two polarization controllers and the polarization beam splitter, modulations of a pi/2 initial phase and an orthogonal polarization state of interference light are realized, two beams of differential interference signals of equal intensity are created, and balance detection of the differential interference signals is realized by means of the balance detector. Compared with the prior art, the device utilizes the SAGNAC effect to realize a non-contact ultrasonic detection and measurement method, has the characteristics of a simple structure, low cost, small size and high sensitivity, and has a wide range of applications.