Quo vadis, plasmonic optical tweezers?

Conventional optical tweezers based on traditional optical microscopes are subject to the diffraction limit, making the precise trapping and manipulation of very small particles challenging. Plasmonic optical tweezers can surpass this constraint, but many potential applications would benefit from further enhanced performance and/or expanded functionalities. In this Perspective, we discuss trends in plasmonic tweezers and describe important opportunities presented by its interdisciplinary combination with other techniques in nanoscience. We furthermore highlight several open questions concerning fundamentals that are likely to be important for many potential applications. Plasmonics: tweezer opportunities The progress, challenges, and potential applications for research in plasmonic-assisted optical tweezers are highlighted in this Perspective. Kenneth Crozier from the University of Melbourne in Australia describes how plasmonic nanostructures that confine and enhance electromagnetic fields on a sub-wavelength scale allow optical tweezers to operate beyond the diffraction limit of light and trap nanoscale particles. Potential applications for such plasmonic tweezers include nanoparticle manipulation and sensing, use in “lab-on-a-chip” devices such as flow cytometers for biological studies, or cold atom trapping for quantum information processing tasks. However, before these opportunities can be fully realized it is important that issues such as heating, which occurs due to absorption from the metal structures used in plasmonics, and a more complete understanding of the plasmonic trapping process are properly addressed.