We present optical trapping with a 10 nm gap resonant coaxial nanoaperture in a gold film. Large arrays of 600 resonant plasmonic coaxial nanoaperture traps are produced on a single chip via atomic layer lithography with each aperture tuned to match a 785 nm laser source. We show that these single coaxial apertures can act as efficient nanotweezers with a sharp potential well, capable of trapping 30 nm polystyrene nanoparticles and streptavidin molecules with a laser power as low as 4.7 mW. Furthermore, the resonant coaxial nanoaperture enables real-time label-free detection of the trapping events via simple transmission measurements. Our fabrication technique is scalable and reproducible, since the critical nanogap dimension is defined by atomic layer deposition. Thus our platform shows significant potential to push the limit of optical trapping technologies.
Bibliographical noteFunding Information:
This research was supported by the U.S. National Science Foundation (ECCS 1610333 to D.Y., H.-K.C., and S.-H.O.) and NSERC CRD (Grant No. 469469-2014 to K.L.G. and R.G.). D.A.M. acknowledges the National Institutes of Health Biotechnology Training Grant (NIH T32 GM008347). C.T.E. was supported by the NSF Graduate Research Fellowship Program. Device fabrication was performed at the Minnesota Nanofabrication Center at the University of Minnesota, which receives partial support from NSF through the National Nanotechnology Coordinated Infrastructure (NNCI). Electron microscopy measurements were performed at the Characterization Facility, which has received capital equipment from NSF MRSEC.
- Optical trapping
- atomic layer lithography
- coaxial aperture
- gap plasmon
- optical force