Integrated plasmonic tweezers for efficient nanoparticle trapping

Optical tweezing system arises from light-matter interactions which provide light driving force capable of directing a particle to a potential well and to maintain it in a stable position [1]. Recently it has been shown that the use of plasmonic structures makes it possible to overcome the problems of diffraction limit in dielectric since these structures are able to concentrate light in deep subwavelength volumes. The excitation of localized surface plasmons (LSPs) at metal nanoparticles (MNPs) can significantly amplify the electromagnetic field in the vicinity of the nanoantennas, providing an optical gradient force for near-field optical trapping. In such a way, by introducing plasmonic resonators inside tweezing systems, very deep and narrow potential well can be tailored to achieve optical tweezing down to subwavelength particles [2].