Holographic Nano‐Imaging of Terahertz Dirac Plasmon Polaritons in Topological Insulator Antenna Resonators
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- NEST CNR‐Istituto Nanoscienze and Scuola Normale Superiore Piazza San Silvestro 12 Pisa 56127 Italy
- Department of Materials Science and Engineering University of Delaware Newark DE 19716 USA
- Materials Science and Engineering Pennsylvania State University University Park PA 16802 USA
- University College London Electronic and Electrical Engineering London WC1E 7JE UK
Abstract Excitation of Dirac plasmon polaritons (DPPs) in bi‐dimensional materials have attracted considerable interest in recent years, both from perspectives of understanding their physics and exploring their transformative potential for nanophotonic devices, including ultra‐sensitive plasmonic sensors, ultrafast saturable absorbers, modulators, and switches. Topological insulators (TIs) represent an ideal technological platform in this respect because they can support plasmon polaritons formed by Dirac carriers in the topological surface states. Tracing propagation of DPPs is a very challenging task, particularly at terahertz (THz) frequencies, where the DPP wavelength becomes over one order of magnitude shorter than the free space photon wavelength. Furthermore, severe attenuation hinders the comprehensive analysis of their characteristics. Here, the properties of DPPs in real TI‐based devices are revealed. Bi 2 Se 3 rectangular antennas can efficiently confine the propagation of DPPs to a single dimension and, as a result, enhance the DPPs visibility despite the strong intrinsic attenuation. The plasmon dispersion and loss properties from plasmon profiles are experimentally determined, along the antennas, obtained using holographic near‐field nano‐imaging in a wide range of THz frequencies, from 2.05 to 4.3 THz. The detailed investigation of the unveiled DPP properties can guide the design of novel topological quantum devices exploiting their directional propagation.
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- NONE; SC0017801
- OSTI ID:
- 2263501
- Alternate ID(s):
- OSTI ID: 2263502
- Journal Information:
- Small, Journal Name: Small; ISSN 1613-6810
- Publisher:
- Wiley Blackwell (John Wiley & Sons)Copyright Statement
- Country of Publication:
- Germany
- Language:
- English
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