Optical imaging of transient acoustic fields using a phase contrast method

TL;DR

This paper introduces a phase-contrast optical system for tomographic imaging of transient acoustic pressure fields, enabling detailed visualization of pressure variations over time.

Contribution

The paper presents a novel Fourier filtering-based phase contrast method for optical imaging of transient acoustic fields, improving upon traditional schlieren techniques.

Findings

Successful experimental imaging of pressure fields from broadband acoustic pulses

Reconstruction of pressure distributions over time after source excitation

Discussion of system limitations and potential applications

Abstract

A coherent phase-contrast optical system has been designed and tested for tomographic imaging of pressure fields from experimental transient acoustic signals. The system is similar to the pulsed, central-order schlieren method, but uses a Fourier filtering technique that images the actual acoustic pressure field, where the former technique reconstructs only the absolute value of the field. Simulations of the system are performed using a single-cycle sine-wave acoustic pulse. Experimental images resulting from a broad-band Gaussian pulse input to an underwater piezoceramic transducer array are presented. Relative pressure field s are reconstructed in space over a series of times after the source excitation. Theory and limitations of the phase contrast system are discussed.