Nanoscale imaging of plasmonic hot spots and dark modes with the photothermal-induced resonance technique

Lahiri, B., Holland, G., Aksyuk, V. and Centrone, A. (2013) Nanoscale imaging of plasmonic hot spots and dark modes with the photothermal-induced resonance technique. Nano Letters, 13(7), pp. 3218-3224. (doi: 10.1021/nl401284m)

Abstract

The collective oscillation of conduction electrons, responsible for the localized surface plasmon resonances, enables engineering nanomaterials by tuning their optical response from the visible to terahertz as a function of nanostructure size, shape, and environment. While theoretical calculations helped tremendously in understanding plasmonic nanomaterials and optimizing their light matter interaction, only a few experimental techniques are available to study these materials with high spatial resolution. In this work, the photothermal-induced resonance (PTIR) technique is applied for the first time to image the dark plasmonic resonance of gold asymmetric split ring resonators (A-SRRs) in the mid-infrared (IR) spectral region with nanoscale resolution. Additionally, the chemically specific PTIR signal is used to map the local absorption enhancement of poly(methyl methacrylate) coated on A-SRRs, revealing hot spots with local enhancement factors up to ≈30 at 100 nm lateral resolution. We argue that PTIR nanoscale characterization will facilitate the engineering and application of plasmonic nanomaterials for mid-IR applications.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Lahiri, Dr Basudev
• Authors: Lahiri, B., Holland, G., Aksyuk, V., and Centrone, A.
• College/School: College of Science and Engineering > School of Engineering
• Journal Name: Nano Letters
• Publisher: American Chemical Society
• ISSN: 1530-6984
• ISSN (Online): 1530-6992