Optical Control over Thermal Distributions in Topologically Trivial and Non-Trivial Plasmon Lattices

Emergent from the discrete spatial periodicity of plasmonic arrays, surface lattice resonances (SLRs) are characterized as dispersive, high-quality polaritonic modes that can be selectively excited at specific points in their photonic band structure by plane-wave light of varying frequency, polarization, and angle of incidence. Room-temperature Bose- Einstein condensation of exciton polaritons, lasing, and nonlinear matter-wave physics have all found origins in SLR systems, but to date, little attention has been paid to their thermal behavior. Here, we combine analytical theory and numerical calculations to investigate the photothermal properties of SLRs in periodic 1D and 2D arrays of plasmonic nanoparticles coupled to each other and to the electromagnetic far-field via transverse radiation. Specifically, we demonstrate how to create steady-state SLR thermal gradients spanning from the nanoscale to hundreds of microns that are actively controllable using light in spite of heat diffusion. We also demonstrate the surprising ability to localize thermal gradients at the lattice edges in topologically non-trivial SLR dimer lattices, thereby establishing a class of extraordinary thermal responses that are unconventional in ordinary materials. This work exposes a new direction in thermoplasmonics that has only just now begun to be explored.