Passive Photoacoustic Effect

TL;DR

This paper introduces a passive photoacoustic effect where moving droplets generate acoustic waves using continuous laser light, validated through analysis and simulations, with potential applications in high-throughput cytometry.

Contribution

It presents a novel passive photoacoustic effect mechanism using moving droplets and continuous laser, expanding the understanding of photoacoustic wave generation without active modulation.

Findings

Validated the passive photoacoustic effect through theoretical analysis and simulations.

Demonstrated that moving droplets can generate photoacoustic waves with continuous laser.

Potential application in high-throughput photoacoustic cytometry.

Abstract

Photoacoustic effect refers to the acoustic generation induced by laser irradiation, where nanosecond pulsed laser source is normally used to provide instantaneous heating and thermoelastic expansion of the sample. More generally, photoacoustic generation requires active intensity modulation of laser source to produce sharp temperature gradient, which is key to generate acoustic wave. In this paper, we propose a novel photoacoustic effect from moving droplet, which generates photoacoustic wave by a non-modulated continuous-wave laser. When the droplet moves through the laser spot area, it can be heated up and cooled down instantaneously, generating photoacoustic waves. We name it passive photoacoustic effect. Theoretical analysis and simulation study validated the existence of passive photoacoustic effect. This phenomenon may find potential application in high-throughput photoacoustic cytometry.