Quantitative measurement method of ultrasonic grating phase amplitude

Abstract

The invention discloses a quantitative measurement method of ultrasonic grating phase amplitude. The quantitative measurement method specifically comprises the following steps: expanding and collimating monochromatic light emitted by a light source, then irradiating the ultrasonic grating in a direction perpendicular to an ultrasonic wave propagation direction and transforming through a lens to obtain a diffraction frequency spectrum of the ultrasonic grating; recording the diffraction frequency spectrum of the ultrasonic grating, calculating to obtain diffraction light intensity ratio of the diffraction frequency spectrum, substituting the diffraction light intensity ratio into a quantitative relation expression between the diffraction light intensity ratio and the ultrasonic grating phase amplitude to solve the phase amplitude of the ultrasonic grating. The quantitative measurement method of ultrasonic grating phase amplitude has the advantages that the quantitative measurement method is capable of obtaining average phase amplitude of a phase grating, quick in measurement speed, easily realizing automatic measurement, applicable to phase amplitude measurement of sine or cosine phase grating, especially applicable to measurement of dynamic periodic phase objects and simple to operate.

Description

technical field [0001] The invention belongs to the technical field of optical measurement and measurement, in particular to a quantitative measurement method for the phase amplitude of an ultrasonic grating. Background technique [0002] Ultrasonic wave is a kind of longitudinal mechanical stress wave. When the ultrasonic wave propagates in a transparent medium, it will cause a periodic elastic strain of the medium density in time and space, resulting in a corresponding change in the refractive index of the medium. If the acousto-optic action distance is small, since the speed of light is much greater than the speed of sound, when the light wave passes through, the refractive index of the medium changes periodically with the space, and its phase is modulated, just like passing through a sinusoidal phase grating, which is called an ultrasonic grating. Ultrasonic gratings are mainly divided into two types: ultrasonic traveling wave gratings and ultrasonic standing wave gratin...

AI Technical Summary

Problems solved by technology

Some of these technologies have very complicated optical paths; some need to take multiple images, which are not suitable for fast dynamic phase objects; some need to scan point by point, and the process takes a long time; some unwrapping algorithms are complex, etc.

These methods are mostly applied to biological cells and other spatial low-frequency non-periodic phase objects, and do not consider the diffraction characteristics of dynamic and spatial high-frequency phase objects. Quantitative phase measurement of ultrasonic grating phase amplitude is not necessarily applicable, and it is not easy to implement. No related reports

Images