Optical Measurement of Sound Fields Information Using Mach-Zehnder Interferometer

An optical method for measuring information of sound fields using the Mach-Zehnder interferometer is described. The Mach-Zehnder interferometer is advantageous for obtaining quantitative measurements of phase values in comparison to other visualization methods. In this study, we simultaneously investigate a two-dimensional data acquisition system for the projection image of an optical phase deviation in proportion to sound fields below the frequency of 2.16 MHz. In the experiment, the charge-coupled device (CCD) camera is used as a function of a mean value detector. The experimental results of the optical phase deviation along the ultrasound axis are useful as primary data for estimating the sound pressure. The two-dimensional measurement system using a CCD camera proposed in this paper has the advantages of acquiring the data in a short time when used in an environment where the measurement conditions change.