Tunable terahertz topological edge and corner states in designer surface plasmon crystals

Abstract

In this work, we study topological edge and corner states in two-dimensional (2D) Su-Schrieffer-Heeger lattices from designer surface plasmon crystals (DSPCs), where the vertical confinement of the designer surface plasmons enables signal detection without the need of additional covers for the sample. In particular, the formation of higher-order topological insulator can be determined by the two-dimensional Zak phase, and the zero-dimensional subwavelength corner states are found in the designed DSPCs at the terahertz (THz) frequency band together with the edge states. Moreover, the corner state frequency can be tuned by modifying the defect strength, i.e., the location or diameter of the corner pillars. This work may provide a new approach for confining THz waves in DSPCs, which is promising for the development of THz topological photonic integrated devices with high compactness, robustness and tunability.

Terahertz Metamaterials for Free-Space and on-Chip Applications: From Active Metadevices to Topological Photonic Crystals

“…This is in essence originated from the larger bulk bandgaps with a larger lattice asymmetry. Apart from the THz waveguides and lasers, tunable terahertz topological edge and corner states in designer surface plasmon crystals were also reported recently (Figure 11(d)) [156]. In the type of Su-Schrieffer-Heeger lattice, symmetry is broken by modulating the intra-cell coupling strength (d 1 ) and inter-cell coupling strength (d 2 ).…”

“…Semiconductors would be an outstanding candidate for active metadevices if they could be integrated with CMOS-compatible fabrication, and more materials and physics should be explored for integrated metadevices to accelerate the relaxation of carrier dynamics for a higher modulation speed. With the development of the nextgeneration communications, more complex reconfigurable EM metasystems would be indispensable for future daily E z component of the bulk states (in black dots), edge states (in blue dots), and corner states (in red dots) are shown [156]. (e) 3D-printed terahertz topological waveguides [157].…”

“…(c) Unidirectional transmission with different types of VPCs [155]. (d) THz designer surface plasmon crystal with a square lattice of metallic pillars standing on a metal surface.E z component of the bulk states (in black dots), edge states (in blue dots), and corner states (in red dots) are shown[156]. (e) 3D-printed terahertz topological waveguides[157].…”

Topological edge state assisted dynamically tunable microwave propagations in photonic crystals

“…The development of novel optical frameworks that can be utilized to manipulate light is a significant area of research in photonics. In the past few decades, many artificially engineered materials such as photonic crystals (PhCs) [1,2], metamaterials [3], and plasmonic systems [4,5] served an important role in the development of photonic devices. Nevertheless, more substantial technologies that are impervious to perturbations, flaws, and disorders are being sought after by contemporary scientific advancements.…”

A pixelated frequency-agile metasurface for broadband terahertz molecular fingerprint sensing

“…The proposed micro/nanophotonics can overcome the bottleneck by strongly enhancing the near-field of subwavelength resonators 3,4 to address some THz practical applications, 5,6 which promote unprecedented control of light at will. [7][8][9][10][11][12][13][14][15][16] If the resonance and absorption fingerprints luckily overlap in the spectrum, the enhanced nearfield will intensify the molecular-resonator coupling, [17][18][19][20] which greatly affects the linewidth and intensity of the resonance, so that the molecular fingerprints can be extracted from the change. Nevertheless, the achieved performance is still far from ideal since the resonant of the unit is easily affected by the surrounding environment and exhibits a frequency drift, which leads to the misalignment of the designed overlap.…”