When Plasmonic Colloids Meet Optical Vortices -- A Brief Review

TL;DR

This review explores how optical vortex beams interact with plasmonic colloids, affecting their dynamics, assembly, and Brownian motion, with emphasis on optical forces, spin-orbit effects, and recent experimental insights.

Contribution

It provides a comprehensive overview of recent research on trapping and manipulating plasmonic colloids using optical vortices, highlighting the role of optical scattering, absorption, and angular momentum effects.

Findings

Optical vortices can trap and manipulate plasmonic colloids effectively.

Spin-orbit coupling influences colloid dynamics and assembly.

Enhanced Brownian motion observed under vortex-lattice illumination.

Abstract

Structured light has emerged as an important tool to interrogate and manipulate matter at micron and sub-micron scale. One form of structured light is an optical vortex beam. The helical wavefront of these vortices carry orbital angular momentum which can be transferred to a Brownian colloid. When the colloid is made of metallic nanostructures, such as silver and gold, resonant optical effects play a vital role, and the interaction leads to complex dynamics and assembly. This brief review aims to discuss some recent work on trapping plasmonic colloids with optical vortices and their lattices. The role of optical scattering and absorption has important implications on the underlying forces and torques, which is specifically enunciated. The effect of spin and orbital angular momentum in an optical vortex can lead to spin-orbit coupling dynamics, and these effects are highlighted with examples from the literature. In addition to assembly and dynamics, enhanced Brownian motion of plasmonic colloids under the influence of a vortex-lattice is discussed. The pedagogical aspects to understand the interaction between optical vortex and plasmonic colloids is emphasized.