Enhanced and controllable reflected group delay based on Tamm surface plasmons with Dirac semimetals

Abstract

In this paper, the reflected group delay from a multilayer structure where bulk Dirac semimetals (BDS) is coated on one-dimensional photonic crystal (1D PC) separated by a spacer layer is investigated theoretically. It is shown that the group delay of reflected beam in this structure can be significant enhanced negatively and can be switched from negative to positive. The enhanced group delay originates from the steep phase change caused by the excitation of optical Tamm state (OTS) at the interface between the BDS and spacer layer. Moreover, the positive and negative group delay can be actively tuned through the Fermi energy and the relaxation time of the BDS. We believe that this enhanced and tunable delay scheme has important research significance for fabrication of optical delay devices.

Coexistence of giant Goos–Hänchen shift and high reflectance in Dirac semimetal based multilayered structure

“…They have proved that dynamic tuning of the group delay value can be achieved by varying the Fermi energy of the BDS via an external voltage. 22 Jiang et al have designed a perfect absorber based on BDS metamaterials and realized tunable absorption by applying a bias voltage to change the Fermi energy of the BDS. 23 In addition, the BDS also has other superior physical properties to monolayer graphene, including a lower plasmonic loss, better structural stability and easier processing.…”

Topologically originated optical analog of electromagnetically induced reflectance in Dirac semi-metal based photonic structure

“…In atomic systems, EIT is a quantum interference phenomenon between two excitation pathways [11]. Researchers have been actively studying the optical analog of EIT and EIR in various photonic crystals [12] and photonic metamaterials [13][14][15]. Recently, Shen et al reported an all-optical analog to electromagnetically induced transparency based on higher-order topological states [16].…”

“…Lu et al investigated optical Tamm states in hetero-structures with highly dispersive planar plasmonic metamaterials to show the EIR-like effect. In the search for new plasmonic materials, bulk Dirac semimetals (BDS) are becoming more significant due to their ultrahigh carrier mobility and tunable conductivity [15,[22][23][24]. The control over Fermi energy and relative permittivity make it a suitable plasmonic material for photonic applications [25].…”