title: Enhancing nanoparticle electrodynamics with gold nanoplate mirrors.
abstract: Mirrors and optical cavities can modify and enhance matter-radiation interactions. Here we report that chemically synthesized Au nanoplates can serve as micrometer-size mirrors that enhance electrodynamic interactions. Because of their plasmonic properties, the Au nanoplates enhance the brightness of scattered light from Ag nanoparticles near the nanoplate surface in dark-field microscopy. More importantly, enhanced optical trapping and optical binding of Ag nanoparticles are demonstrated in interferometric optical traps created from a single laser beam and its reflection from individual Au nanoplates. The enhancement of the interparticle force constant is ≈20-fold more than expected from the increased intensity due to standing wave interference. We show that the additional stability for optical binding arises from the restricted axial thermal motion of the nanoparticles that couples to and reduces the fluctuations in the lateral plane. This new mechanism greatly advances the photonic synthesis of ultrastable nanoparticle arrays and investigation of their properties.
authors.affiliation: The James Franck Institute, The University of Chicago , 929 East 57th Street, Chicago, Illinois 60637, United States.
authors.forename: Zijie
authors.initials: Z
authors.lastname: Yan
authors.forename: Ying
authors.initials: Y
authors.lastname: Bao
authors.forename: Uttam
authors.initials: U
authors.lastname: Manna
authors.forename: Raman A
authors.initials: RA
authors.lastname: Shah
authors.forename: Norbert F
authors.initials: NF
authors.lastname: Scherer