Photothermal effects in mobile nanotweezers

Abstract

Magnetically driven mobile plasmonic nanotweezers [1] are potential candidates for various device applications pertaining to optical manipulation which are otherwise difficult to achieve using existing techniques. When illuminated, plasmonic nanoantennas generate enhanced localized electric field which imparts mechanical gradient force to trap sub-wavelength sized objects. In addition to the trapping force, there are also other effects present in a plasmonic system due to efficient absorption of electromagnetic energy. In this paper, we have theoretically investigated intrinsic plasmonic heating and resulting fluid convection for mobile nanotweezers. The temperature rise and fluid flow are calculated as a function of incident light intensity and position of the nanotweezer inside the chamber where we have assumed the geometries and experimental conditions given in reference [1]. In addition, we have investigated the possible role of fluid confinement in convective flows generated by the nanotweezer. The detailed thermal and hydrodynamic study brings an insight to different parameters that can influence the trapping performance of mobile nanotweezers and their applicability for practical purposes.