Plasmonic Fano Resonance in Homotactic Aluminum Nanorod Trimer: the Key Role of Coupling Gap
- PDF / 975,821 Bytes
- 7 Pages / 595.276 x 790.866 pts Page_size
- 18 Downloads / 168 Views
Plasmonic Fano Resonance in Homotactic Aluminum Nanorod Trimer: the Key Role of Coupling Gap Xupeng Zhu 1 & Shi Zhang 2 & Huimin Shi 3 & Mengjie Zheng 2 & Yasi Wang 2 & Renglai Wu 1 & Jun Quan 1 & Jun Zhang 1 & Huigao Duan 2 Received: 17 December 2019 / Accepted: 27 January 2020 # Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract Recently, the Fano effect of aluminum nanostructures has attracted a lot of attentions in several detector and sensor applications, but the role of coupling gap in it remains unintuitive. In this paper, a homotactic aluminum rod trimer (HART) is designed to form the plasmonic Fano resonances and visualize the important role of coupling gap size. The plasmon hybridization model and far field images were used to qualitatively describe the formation mechanism of Fano resonance. The simulation results intuitively show that the Fano dip of HART with a smaller coupling gap size has a higher red-shift speed when increasing the refractive index of surrounding environment or the length of HART with a fixed axial ratio (LS/LL = 0.6). Our study provides the insights to the key role of coupling gap in the performance of Fano structures. Keywords Plasmon . Fano resonance . Aluminum nanorods . Far field . Coupling gap
Introduction Plasmonic Fano resonances, which arise from the coupling and the interference of the superradiant and the subradiant surface plasmon modes in metal micro-nanostructures [1–4], have been used for a variety of applications including plasmonic detector and biosensors due to their narrow spectral linewidth, large induced field enhancements and asymmetric line shapes [5–7]. In past decades, silver (Ag) and gold (Au) have become the mostly used materials to fabricate Fano structures due to their favorable dielectric properties [8–11]. But the related applications of Ag and Au micro-nanostructures in some regime, e.g., ultraviolet,
* Jun Quan [email protected] * Jun Zhang [email protected] * Huigao Duan [email protected] 1
School of Physics Science and Technology, Lingnan Normal University, Zhanjiang 524048, China
2
College of Mechanical and Vehicle Engineering, State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha 410082, China
3
Center for Research on Leading Technology of Special Equipment, School of Mechanical and Electric Engineering, Guangzhou University, Guangzhou 510006, China
are limited by the strong s-d interband transition (2.4 eV for Au and 3.8 eV for Ag, respectively) [12, 13], in which the photons with energies above the interband threshold predominantly excite electron–hole pairs instead of coherent conduction electron oscillations. By comparison, aluminum (Al) is a more potential material for plasmonic Fano resonances due to the excellent oxidation stability and a wide tunability ranging from the ultraviolet to visible regime (only a narrow energy interval around the interband transition at 1.5 eV) [14–17]. Besides, Al is an abundant, cheap, and sustainable material which e
Data Loading...
