Photophoretic Trapping: Fundamentals, Advances and Future Directions

TL;DR

This review comprehensively explains the physics, experimental setups, and applications of photophoretic forces, highlighting their potential for stable particle manipulation and future research directions in various scientific fields.

Contribution

It systematically unifies theoretical, experimental, and application aspects of photophoretic trapping, advancing understanding and guiding future research in this rapidly evolving area.

Findings

Photophoretic forces are significantly stronger than radiation pressure.

Stable 3D trapping of particles is achievable with specific configurations.

Photophoretic trapping has promising applications in space, aerosol science, and displays.

Abstract

Photophoretic forces, several orders of magnitude stronger than radiation pressure, enable particle trapping at remarkably low optical intensities and have opened pathways to applications in aerosol science, free-space 3D volumetric displays, and even deployment of lightweight payloads in space. In this review, we provide a comprehensive explanation of the underlying physics of photophoretic forces and how they facilitate stable three-dimensional manipulation of absorbing particles. We examine the experimental configurations that enable robust trapping, and we detail the physical parameters that govern the magnitude and behavior of photophoretic forces in these geometries. The rich dynamical phenomena exhibited by photophoretically trapped particles are discussed alongside current and emerging applications and possible future research directions. This review thus attempts to systematically unify the theoretical, experimental, and application-oriented aspects of photophoretic trapping, with the aim of advancing and strengthening research in this rapidly developing field.