Dynamics of optically directed assembly and disassembly of plasmonic nanoplatelet arrays

TL;DR

This study explores the assembly and disassembly dynamics of plasmonic nanoplatelet arrays manipulated by optical line traps, revealing complex interactions driven by multipolar plasmon modes and their potential for advanced optical technologies.

Contribution

It introduces the first detailed investigation of nanoplatelet array dynamics, highlighting the role of multipolar plasmon modes and phase gradient control in optical matter assembly.

Findings

Nanoplatelet arrays exhibit slower, more precise assembly compared to nanospheres.

Electrodynamics simulations show multipolar modes induce complex interactions.

Strong temporal and spatial correlations are observed among particles.

Abstract

Studies of nanoparticle-based optical matter have only considered spherical constituents. Yet nanoparticles with other shapes are expected to have different local electromagnetic field distributions and therefore interactions with neighbors in optical matter arrays. Therefore, one would expect their dynamics to be different as well. We investigate directed-assembly of ordered arrays of plasmonic nanoplatelets in optical line traps demonstrating reconfigurability of the array by altering the phase gradient via holographic beam shaping. The weaker gradient forces on and resultant slower motion of the nanoplatelets as compared with plasmonic nanospheres allows precise study of their assembly and disassembly dynamics. Both temporal and spatial correlations are detected between particles separated by some hundreds of nanometers to several microns. Electrodynamics simulations reveal the presence of multipolar plasmon modes that induce short range (near-field) and longer range electrodynamic interactions. These interactions cause both the strong correlations and the non-uniform dynamics observed. Our findings demonstrate new opportunities to generate complex adressable optical matter by exploiting interference between mutipolar plamon modes and create novel active optical technology.