Plasmonic Nano-Antenna Design for Enhanced Second Harmonic Generation

Jonathan Bar-David Department of Applied Physics, The Benin School of Engineering and Computer Science, The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem, Israel Uriel Levy Department of Applied Physics, The Benin School of Engineering and Computer Science, The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem, Israel

Metallic Nano-antennas are known to enhance the electric field in their vicinity by orders of magnitude, thus enhancing light-matter interactions [1].One of the best examples for enhanced light-matter interactions around nano-antennas is the nonlinear process of second harmonic generation (SHG), which is dependent on the incident optical power in a quadratic fashion, and therefore serves as a direct measure for the enhancement of the electric field. While metals have strong natural nonlinearity, the proper nonlinear mode-matching conditions must be fulfilled, otherwise the nonlinear response will be diminished and will not be coupled to radiativemodes [2,3].

In this work we design and demonstrate a new type of gap nano-antenna for the purpose of enhancing SHG by considering phase-matching conditions and optimizing our design for generating a second harmonic from a principal pump wavelength of 800 nm. In order to overcome intraband transitions in Au, we have fabricated nano-antennas of Al, and characterized their linear and nonlinear response by far-field transmission spectroscopy and short pulse illumination. We report the results and conclusions of our research and discuss the general considerations of tailoring nano-antennas for specific purposes.

References:

[1] Novotny L, van Hulst N. Antennas for light. Nat Photon. 2011 Feb;5(2):83–90.

[2] Thyagarajan K, Rivier S, Lovera A, Martin OJF. Enhanced second-harmonic generation from double resonant plasmonic antennae. Opt Express. 2012 Jun 4;20(12):12860–5.

[3] Ginzburg P, Krasavin A, Sonnefraud Y, Murphy A, Pollard RJ, Maier SA, et al. Nonlinearly coupled localized plasmon resonances: Resonant second-harmonic generation. Phys Rev B. 2012 Aug 13;86(8):085422.

jonathan.bardavid@mail.huji.ac.il









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