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Tailoring second-harmonic generation in single L-shaped plasmonic nanoantennas from the capacitive to conductive coupling regime

Tailoring second-harmonic generation in single L-shaped plasmonic nanoantennas from the capacitive to conductive coupling regime
Tailoring second-harmonic generation in single L-shaped plasmonic nanoantennas from the capacitive to conductive coupling regime
We investigate the efficiency of second-harmonic generation (SHG) over the transition from capacitive to conductive coupling in orthogonal L-shaped dimer gold antennas. By tuning both the gap and antenna length, the bonding and antibonding resonances are individually addressed. Results on the intensity and polarization of SHG are compared quantitatively with microscopic numerical simulations taking into account the nanoscale nonlinear surface dipole distribution, elucidating the interplay between symmetry at macroscopic and microscopic levels and optical resonance effects. Microscopic modeling reveals strong cancellations of nonlinear dipoles by capacitive coupling in plasmonic nanogaps, resulting in only small changes in SHG efficiency despite large local field enhancement in the gap. Experimentally, irreproducible polarization properties are obtained in a range of parameters associated with strong optical near fields in the gap of the antennas, which is interpreted as a consequence of nanoscopic asymmetries inherited from the fabrication process. Our results demonstrate that nanoscopic defects can either strongly impact the nonlinear optical emission or have a barely detectable influence depending on the excited optical resonance and associated optical near-field distribution. These results provide useful design rules to optimize the design of nonlinear plasmonic nanostructures.
second-harmonic generation, SHG, plasmonics, nanoantennas, polarization conversion, metasurface
1592-1601
Black, Leo-Jay
867ac86c-8bc2-452e-9576-903ca2be6ea2
Wiecha, Peter R.
f297f06e-c298-4f3b-8cb9-98ccd21cd124
Wang, Yudong
c48bcc7c-4cb4-468c-af4e-d1e601222009
de Groot, C. H.
92cd2e02-fcc4-43da-8816-c86f966be90c
Paillard, Vincent
42984d54-6434-45a6-9b53-41b51bc1f6f6
Girard, Christian
85fb41ad-6753-46a1-b550-b719cf329a52
Muskens, Otto L.
2284101a-f9ef-4d79-8951-a6cda5bfc7f9
Arbouet, Arnaud
3c681c1a-31cf-45dc-9f7f-604b81ebde4e
Black, Leo-Jay
867ac86c-8bc2-452e-9576-903ca2be6ea2
Wiecha, Peter R.
f297f06e-c298-4f3b-8cb9-98ccd21cd124
Wang, Yudong
c48bcc7c-4cb4-468c-af4e-d1e601222009
de Groot, C. H.
92cd2e02-fcc4-43da-8816-c86f966be90c
Paillard, Vincent
42984d54-6434-45a6-9b53-41b51bc1f6f6
Girard, Christian
85fb41ad-6753-46a1-b550-b719cf329a52
Muskens, Otto L.
2284101a-f9ef-4d79-8951-a6cda5bfc7f9
Arbouet, Arnaud
3c681c1a-31cf-45dc-9f7f-604b81ebde4e

Black, Leo-Jay, Wiecha, Peter R., Wang, Yudong, de Groot, C. H., Paillard, Vincent, Girard, Christian, Muskens, Otto L. and Arbouet, Arnaud (2015) Tailoring second-harmonic generation in single L-shaped plasmonic nanoantennas from the capacitive to conductive coupling regime. ACS Photonics, 2 (11), 1592-1601. (doi:10.1021/acsphotonics.5b00358).

Record type: Article

Abstract

We investigate the efficiency of second-harmonic generation (SHG) over the transition from capacitive to conductive coupling in orthogonal L-shaped dimer gold antennas. By tuning both the gap and antenna length, the bonding and antibonding resonances are individually addressed. Results on the intensity and polarization of SHG are compared quantitatively with microscopic numerical simulations taking into account the nanoscale nonlinear surface dipole distribution, elucidating the interplay between symmetry at macroscopic and microscopic levels and optical resonance effects. Microscopic modeling reveals strong cancellations of nonlinear dipoles by capacitive coupling in plasmonic nanogaps, resulting in only small changes in SHG efficiency despite large local field enhancement in the gap. Experimentally, irreproducible polarization properties are obtained in a range of parameters associated with strong optical near fields in the gap of the antennas, which is interpreted as a consequence of nanoscopic asymmetries inherited from the fabrication process. Our results demonstrate that nanoscopic defects can either strongly impact the nonlinear optical emission or have a barely detectable influence depending on the excited optical resonance and associated optical near-field distribution. These results provide useful design rules to optimize the design of nonlinear plasmonic nanostructures.

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More information

e-pub ahead of print date: 19 October 2015
Published date: 18 November 2015
Keywords: second-harmonic generation, SHG, plasmonics, nanoantennas, polarization conversion, metasurface
Organisations: Quantum, Light & Matter Group

Identifiers

Local EPrints ID: 385890
URI: http://eprints.soton.ac.uk/id/eprint/385890
PURE UUID: 22cf247e-1391-4167-8e02-38f154b27d01
ORCID for C. H. de Groot: ORCID iD orcid.org/0000-0002-3850-7101
ORCID for Otto L. Muskens: ORCID iD orcid.org/0000-0003-0693-5504

Catalogue record

Date deposited: 25 Jan 2016 16:51
Last modified: 29 Oct 2019 01:55

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