Photoacoustic effect generated by moving optical sources: Motion in three dimensions

Area of Science:

• Acoustics
• Optics
• Wave phenomena

Background:

• The photoacoustic effect is typically generated using pulsed or amplitude-modulated radiation.
• A steady source moving in space can also produce the photoacoustic effect.
• Investigating photoacoustics from moving sources in 3D is less explored.

Purpose of the Study:

• To investigate the properties of the photoacoustic effect generated by moving sources in three dimensions.
• To analyze the mathematical relationship between moving photoacoustic sources and electromagnetics.
• To explore different motion regimes including sub-sonic, sonic, and super-sonic speeds, as well as oscillations.

Main Methods:

• Mathematical modeling of a 3D photoacoustic point source.
• Analysis of rectilinear motion at speeds relative to the sound speed (lower than, equal to, greater than).
• Investigation of an oscillating point source and a Gaussian source moving at the sound speed.

Main Results:

• The mathematics for a moving photoacoustic point source is analogous to the Lienard-Wiechert potential for a moving point charge.
• Rectilinear motion at various speeds and oscillating sources were analyzed.
• A bounded amplification effect was observed for a Gaussian source moving at the sound speed.

Conclusions:

• The photoacoustic effect can be generated by steady moving sources in 3D.
• The mathematical framework for moving photoacoustic sources shares similarities with electromagnetics.
• A bounded amplification effect exists for specific 3D moving sources, differing from 1D scenarios.