Uncovering surface plasmon optical resonances in nanohole arrays through interferometric photoemission electron microscopy

Journal Article · 21 February 2022 · Applied Physics Letters

DOI: https://doi.org/10.1063/5.0082481 · OSTI ID:1893139

Crampton, Kevin T.  ^[1]; Joly, Alan G.  ^[1]; El-Khoury, Patrick Z.  ^[1]

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1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

In this work, the role of surface plasmon polaritons (SPPs) in nanohole array optical extinction spectra is explored using a time-resolved technique capable of isolating the air/metal interfacial SPP contribution to the typical Fano profile in optical transmission curves. A pair of interferometrically locked broad-band femtosecond pulses is used to launch SPPs from lithographically patterned plasmonic nanohole arrays. SPPs launched in the co- and counter-propagating directions are probed using a third probe pulse in a photoemission electron microscope. Using this approach, we record interferometric SPP–SPP linear autocorrelations that selectively report on the resonances of SPPs launched from arrays of varying pitches and hole diameters. Aside from advancing an approach to selective SPP spectroscopy, we illustrate that resonant coupling in the counter-propagating direction may be exploited to control the spatial, temporal, and spectral characteristics of SPPs. For the counter-propagating direction, we show that tuning the array pitch near the fundamental plasmon resonance generates color-tuned (~770–820 nm), narrow bandwidth SPPs, and the bandwidth may be controlled by changing the ratio of pitch to hole diameter. The SPP resonances we recover through Fourier transforms of the interferometric autocorrelations shed light on the classical problem of Fano interference in nanohole array extinction spectra.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States). Environmental Molecular Sciences Laboratory (EMSL)
• Sponsoring Organization: USDOE; USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division; USDOE Office of Science (SC), Biological and Environmental Research (BER)
• Grant/Contract Number: AC05-76RL01830
• OSTI ID: 1893139
• Report Number(s): PNNL-SA-169216
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 8 Vol. 120; ISSN 0003-6951
• Publisher: American Institute of Physics (AIP)Copyright Statement
• Country of Publication: United States
• Language: English