The 67th JSAP Spring Meeting 2020

Presentation information

Oral presentation

3 Optics and Photonics » 3.1 Basic optics and frontier of optics

[15a-B410-1~12] 3.1 Basic optics and frontier of optics

Sun. Mar 15, 2020 9:00 AM - 12:15 PM B410 (2-410)

Takaaki Yano(Tokushima Univ.), Hiroshi Yoshikawa(Saitama Univ.)

11:30 AM - 11:45 AM

[15a-B410-10] Design of plasmonic antennas with double nano-gap resonance

Pin Christophe1, Seiya Fujikawa1, Keiji Sasaki1 (1.RIES, Hokkaido Univ.)

Keywords:plasmonic antenna, quantum emitter, light-matter interactions

Localized surface plasmon resonances (LSPRs) in metallic nanostructures have been studied for several decades but are still actively investigated for their unique properties as optical antenna. Plasmonic nano-antennas have found applications in various field such as sensing, control and enhancement of quantum emitters’ fluorescence, second harmonic generation, optical trapping, and heat generation. Plasmonic resonances occurring in nano-gaps can generate much localized, intense electric fields, confined at a deep subwavelength scale. Although being of fundamental interest for studying and exploiting light-matter interactions in nanotechnologies, precise control of the electric field properties in such nano-gaps requires specific engineering of the plasmonic nano-antenna.
In this work, we investigate different strategies to design multi-resonant plasmonic antennas allowing for confining the light in a single nano-gap at different visible and near-infrared (NIR) wavelengths. For instance, being able to confine the light in a single nano-gap over a broad wavelength range is of prime interest for nanoparticle and molecule spectroscopy applications. However, the plasmon-induced enhancement of the light emission of a quantum emitter increases with the quality factor of the LSPR, which also reduces the spectral range of the LSPR excitation.
The goal of this study is to develop efficient nano-gap antennas for combined applications such as optical trapping using an NIR and visible fluorescence spectroscopy. For each design, we evaluate the field enhancement in the nano-gap as a function of the excitation wavelength, as well as the expected enhancement of the emission rate of a dipole emitter located in the vicinity of the nano-gap. We also consider the effect of asymmetric antenna designs on the emission properties of chiral emitters.