Role of Antenna Modes and Field Enhancement in Second Harmonic Generation from Dipole Nanoantennas

Document Type

Article

Publication Date

1-2015

Publication Source

Optics Express

Abstract

We study optical second harmonic generation from metallic dipole antennas with narrow gaps. Enhancement of the fundamental-frequency field in the gap region plays a marginal role on conversion efficiency. In the symmetric configuration, i.e., with the gap located at the center of the antenna axis, reducing gap size induces a significant red-shift of the maximum conversion efficiency peak. Either enhancement or inhibition of second-harmonic emission may be observed as gap size is decreased, depending on the antenna mode excited at the harmonic frequency. The second-harmonic signal is extremely sensitive to the asymmetry introduced by gap’s displacements with respect to the antenna center. In this situation, second-harmonic light can couple to all the available antenna modes. We perform a multipolar analysis that allows engineering the far-field SH emission and find that the interaction with quasi-odd-symmetry modes generates radiation patterns with a strong dipolar component.

Inclusive pages

1715-1729

ISBN/ISSN

1094-4087

Comments

Permission documentation is on file.

Publisher

Optical Society of America

Volume

23

Peer Reviewed

yes

Issue

2

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