THz Metawires: Near-Field Probing and Super-Focusing in the Far- Infrared

摘要

This report results from a contract tasking University of Bath as follows: We propose to develop a new approach to the guiding and focusing of THz radiation aimed at applications in civil defence imaging and monitoring. Our approach uses what we call a 'metawire', a cylindrical wire decorated with a regular array of grooves. Borrowing on concepts from the engineering of planar metamaterials, such a wire can guide THz radiation with strong confinement in the form of electromagnetic surface modes. In addition, focusing to volumes far below the diffraction limit into the micron and possibly sub- micron level is possible in tapered structures. We have so far conducted proof- of-principle electromagnetic simulations showing the feasibility of this concept, and now want to move to the real-world development of this technology, leading to compact devices for THz probing in confined spaces. Additionally, we want to make a push into active THz near-field probing by designing near-field probes with integrated receivers pumped by hollow-core photonic crystal fibres, to enable flexibility in THz device characterization. Applications of a THz metawire in the civil defence sector are likely to include: a) highly integrated THz guiding and routing structures allowing easy interfacing to sources/detectors b) sensitive THz sensors for explosives, civil defence agents, etc. c) the development of a new THz imaging technology offering possibly sub- micron scale resolution.