Nanoscale Infrared Spectroscopy and Imaging: Enabling Nanoscale Plasmonic/Optical Interrogation of Corrugated Two-dimensional Materials
Abstract
Plasmons, which are oscillations of free electrons in conductive materials, exhibit unique properties such as small spatial extension compared to the wavelength of light, strong interaction with light, and extreme optical enhancement. In particular, graphene plasmons are emerging as a viable platform for rapid electrical manipulation and sub-wavelength confinement of light. In the PI’s current AFOSR YIP grant, the PI investigates the use of ‘corrugated’ graphene structures, i.e., graphene that has been intentionally deformed to yield a smoothly undulating surface, to mimic conventional planar patterning to achieve excitation of higher energy graphene plasmons. In this DURIP proposal, the PI proposes to acquire a dual-mode nano-IR spectroscopy/imaging platform which combines AFM-IR spectroscopy and AFM-based scattering SNOM (s-SNOM) imaging technology to enable nearfield, nano-plasmonic/optical spectroscopy and imaging of plasmonic resonance owing to corrugated topographies of graphene. AFM-IR directly detects light absorbed by the sample by using an AFM probe tip to sense thermal expansion. This thermal expansion depends mainly on the sample’s absorption coefficient and is independent of the other properties of the tip and sample. Simultaneously, AFM-based s-SNOM detects light scattered by nanometer -cale regions directly beneath the AFM probe tip. The scattered field depends on the complex optical constants of both the tip and sample and contains rich information about nano-optical phenomena. By accessing both the non-radiative (AFM-IR) and radiative (s-SNOM) information on plasmonic structures, unique and complementary plasmonic properties of corrugated graphene can be investigated. The success of the research, enabled by the acquisition of a nano-IR spectroscopy/imaging platform, will yield a deeper understanding of the nature of plasmons in corrugated graphene by allowing direct mapping and visualization of plasmonic resonances using dual mode nano-IR.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 28, 2018
- Source ID
- FA95501810405
Entities
People
- SungWoo Nam
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of Illinois Urbana–Champaign