title: Local electron beam excitation and substrate effect on the plasmonic response of single gold nanostars.
abstract: We performed cathodoluminescence (CL) spectroscopy and imaging in a high-resolution scanning electron microscope to locally and selectively excite and investigate the plasmonic properties of a multi-branched gold nanostar on a silicon substrate. This method allows us to map the local density of optical states from the nanostar with a spatial resolution down to a few nanometers. We resolve, both in the spatial and spectral domain, different plasmon modes associated with the nanostar. Finite-difference time-domain (FDTD) numerical simulations are performed to support the experimental observations. We investigate the effect of the substrate on the plasmonic properties of these complex-shaped nanostars. The powerful CL-FDTD combination helps us to understand the effect of the substrate on the plasmonic response of branched nanoparticles.
authors.affiliation: Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700 064, India.
authors.forename: Pabitra
authors.initials: P
authors.lastname: Das
authors.forename: Abhitosh
authors.initials: A
authors.lastname: Kedia
authors.forename: Pandian Senthil
authors.initials: PS
authors.lastname: Kumar
authors.forename: Nicolas
authors.initials: N
authors.lastname: Large
authors.forename: Tapas Kumar
authors.initials: TK
authors.lastname: Chini