Optical Trapping and Manipulation of Nanoparticles on Plasmonic Silicon-Nanostructured Array Coating on Silicon Film

A silicon-nanostructured array coating on silicon film (SAS film) is designed based on the plasmonic optical tweezer and demonstrated for optical trapping and manipulation of nanospheres with negligible impact on the local thermal conditions. The electric field enhancement, optical force, and trapping potential of the SAS film are investigated by the finite element method. The trapping position is affected by the incident light wavelength, structure of the nanoarray, and refractive index of the nanospheres. The presence of four energy wells around the nanoarray suggests that it is possible to trap multiple nanoparticles. Moreover, the circularly polarized light, Gaussian beam, and silicon nanoarray facilitate the trapping of nanoparticles. This study showcases the potential of SAS film as optical tweezers to capture nanoparticles for the development of nanophotonic devices.