Effects of Non-fundamental Nanoantenna Eigenmodes on Two-photon Photoluminescence
Fan-Cheng Lin1*, Wei-Liang Chen2, Feng-Chieh Li2, Yu-Yang Lee2, Yu-Ming Chang2, Jer-Shing Huang1
1Chemistry, National Tsing Hua University, Hsinchu, Taiwan
2Center for Condensed Matter Sciences, National Taiwan University, Taipei, Taiwan
* presenting author:林範誠, email:fc.lin25@gmail.com
Upon resonant excitation, gold plasmonic nanoantennas can generate strongly depolarized two-photon photoluminescence (TPPL), which serves as ideal local broadband visible source for the spectroscopic investigation of nanoantenna eigenmodes [1, 2]. In this work, TPPL emission spectra of three arrays of single-crystalline gold nanoantennas are comprehensively investigated with careful comparison with dark-field scattering spectra and numerically simulated spectra. We demonstrate the modulation of the TPPL spectrum due to the transverse bonding mode, the higher-order bonding modes and the dark anti-bonding modes [2]. Numerical simulations are performed in order to confirm the resonance phenomenon. Our work provides direct experimental evidence on the nanoantenna-mediated near-to-far-field energy coupling and gains insight into the emission spectrum of the TPPL from gold nanoantennas.

[1] Wissert, M. D.; Ilin, K. S.; Siegel, M.; Lemmer, U.; Eisler, H.-J. Coupled Nanoantenna Plasmon Resonance Spectra from Two-Photon Laser Excitation. Nano Lett. 10, 4161-4165 (2010).
[2] Huang, J.-S.; Kern, J.; Geisler, P.; Weinmann, P.; Kamp, M.; Forchel, A.; Biagioni, P.; Hecht, B. Mode Imaging and Selection in Strongly Coupled Nanoantennas. Nano Lett. 10, 2105-2110 (2010).

Keywords: nanoantennas, two-photon photoluminescence, plasmonic resonance, dark mode