Work

Sensing Thermophoretic Forces by Nanoplasmonic Actuators with Interferometric Scattering Readout

Year: 2024

Type: article

Abstract: Noble metal nanoparticles (NPs) represent nanoscale, optically addressable heat sources whose temperature gradients give rise to thermophoretic forces that can act back on the NPs. Herein we investigate 20 nm Ag NPs bound via molecular tethers to a 20 nm thin Au film as nanoplasmonic actuators that generate a local temperature gradient and simultaneously act as optical sensors of forces that induce their displacement from their equilibrium position. Forces of sufficient magnitude to affect the NP–film distance modulate the interferometric scattering (iSCAT) signal of the individual NPs and become detectable due to the distance-dependent damping of the NP scattering in the vicinity of the metal film. With total incident power densities within a range between 1.40 and 4.80 kW cm –2, the experiments reveal a continuous decay in the NP iSCAT signal, consistent with a decrease in the NP–film separation due to an attractive thermophoretic force.

Source: Nano Letters

DOI: 10.1021/acs.nanolett.4c05459

Authors: Yixin Mei, Aidan Oi, Leslie Velasco, Sonia Zahara, Björn M. Reinhard

Institution: Boston University

Language: English

Topic: Orbital Angular Momentum in Optics

Subfield: Atomic and Molecular Physics, and Optics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: green

Funders: National Institutes of Health, National Cancer Institute, National Institute of General Medical Sciences

Awards: G1222805054, G4259077146, G9000129281