Picture of flying drone

Award-winning sensor signal processing research at Strathclyde...

The Strathprints institutional repository is a digital archive of University of Strathclyde's Open Access research outputs. Strathprints provides access to thousands of Open Access research papers by University of Strathclyde researchers, including by Strathclyde researchers involved in award-winning research into technology for detecting drones. - but also other internationally significant research from within the Department of Electronic & Electrical Engineering.

Strathprints also exposes world leading research from the Faculties of Science, Engineering, Humanities & Social Sciences, and from the Strathclyde Business School.

Discover more...

Assessing the location of surface plasmons over nanotriangle and nanohole arrays of different size and periodicity

Correia-Ledo, Debby and Gibson, Kirsty F. and Dhawan, Anuj and Couture, Maxime and Vo-Dinh, Tuan and Graham, Duncan and Masson, Jean-Francois (2012) Assessing the location of surface plasmons over nanotriangle and nanohole arrays of different size and periodicity. Journal of Physical Chemistry C, 116 (12). pp. 6884-6892. ISSN 1932-7447

Full text not available in this repository. (Request a copy from the Strathclyde author)


The increasing popularity of surface plasmon resonance (SPR) and surface enhanced Raman scattering (SERS) sensor design based on nanotriangle or nanohole arrays, and the possibility to manufacture substrates at the transition between these plasmonic substrates, makes them ideal candidates for the establishment of structure property relationships. This work features near diffraction-limited Raman images and finite-difference time-domain (FDTD) simulations of nanotriangle and nanohole array substrates, which clearly demonstrate that the localization of the hot spot on these SERS substrates is significantly influenced by the ratio of diameter/periodicity (D/P). The experimental and simulation data reveal that the hot spots are located around nanotriangles (D/P = 1), characteristic of localized SPR. Decreasing the D/P ratio to 0.75-0.7 led to the creation of nanohole arrays, which promoted the excitation of a propagating surface plasmon (SP) delocalized over the metal network. The optimal SERS intensity was consistently achieved at this transition from nanotriangles to nanoholes, for every periodicity (650 nm to 1.5 mu m) and excitation wavelength (633 and 785 nm) investigated, despite the presence or absence of a plasmonic band near the laser excitation. Further decreasing the D/P ratio led to excitation of a localized SP located around the rim of nanohole arrays for D/P of 0.5-0.6, in agreement with previous reports. In addition, this manuscript provides the first evidence that the hot spots are positioned inside the hole for D/P of 0.4, with the center being the region of highest electric field and Raman intensity. The compelling experimental evidence and FDTD simulations offer an overall understanding of the plasmonic properties of nanohole arrays as SERS and SPR sensors, which is of significant value in advancing the diversity of applications from such surfaces,