Exploring “Fano resonance”-assisted trapping of core–shell hybrid nanoparticles under femtosecond pulsed excitation using the generalized Lorenz–Mie theory

Abstract

The core–shell type structure of metal-dielectric nanoparticles has great applications in the fields of nanophotonics and biomedical sciences due to the plasmonic properties of metals and field enhancements at metal-dielectric interfaces. The present study reveals critical insights into the influence of these properties on the optical trapping of core–shell nanoparticles, investigated using generalized Lorenz-Mie theory. Specifically, the presence of Fano resonance is discussed based on the size contribution of the core and shell and its influence on the directionality of the scattering force. Furthermore, the effects of optical nonlinearity on the appearance of Fano resonance and trapping efficiency are explored under femtosecond pulsed excitation.