Coupled T-Shaped Optical Antennas with Two Resonances Localized in a Common Nanogap

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• 作者：Katja Dopf ; Carola Moosmann ; Siegfried W. Kettlitz ; Patrick M. Schwab ; Konstantin Ilin ; Michael Siegel ; Uli Lemmer ; Hans-J眉rgen Eisler
• 刊名：ACS Photonics
• 出版年：2015
• 出版时间：November 18, 2015
• 年：2015
• 卷：2
• 期：11
• 页码：1644-1651
• 全文大小：608K
• ISSN：2330-4022

文摘

Resonant optical antennas with nanoscale gaps are of high interest due to their ability to enhance electric fields in localized subdiffraction-limited volumes. They are especially attractive for coupling with quantum emitters. One challenge for applications that exhibit a spectral shift is to fabricate nanoantennas that provide two distinct resonances at the excitation and emission frequency, respectively. We propose a coupled T-shaped nanoantenna structure that provides independently controllable resonances with a common electromagnetic hot spot in the antenna gap. We demonstrate the fabrication of such structures and investigate experimentally and theoretically their spatial, time-integrated spectral- and polarization-dependent electromagnetic field properties. The nanoantennas exhibit two resonances with unique spectral and polarization responses. The resonance wavelengths are independently tailored by varying the geometry of individual T-shaped antennas.