Light structuring photonic hook via temperature mediated effects

Peled, Maya Hen Shor and Maioli, Paolo and Karabchevsky, Alina (2022) Light structuring photonic hook via temperature mediated effects. In: Nanophotonics IX :. Proceedings of SPIE - The International Society for Optical Engineering . SPIE, Virtual, Online. ISBN 9781510651388

Abstract

Optical methods have been studied and used extensively for diagnostics and treatment of bio-tissues and cells. Yet, the quality of these methods is still biased by low optical contrast, background noise and heating. Therefore, the ability to track an object's location in cells and tissues is lacking. Here, we report on a method of optically moving gold nanoparticles in a temperature-mediated manner via a structured light - photonic hook. Since continuous wave (CW) generated photonic hooks are extremely weak in low-contrast media, we amplify the optical forces by using pulsed illumination. Our system consists of a micro-cylinder illuminated by an incident Gaussian pulse, and a mask controlling the asymmetry of the incident light. We show that the generated optical forces are around fifteen orders of magnitude larger than by illuminating with a continuous wave of equivalent average power. The photonic hook is applied to a gold nanoparticle embedded in liquid. By investigating the thermo-optical properties of metallic nanoparticles, we present the displacement of the gold nanoparticle, as a result of the momentum exchange. The displacement and changes in polarizability of the gold nanoparticle are examined.