title: Dielectric tube waveguides with absorptive cladding for broadband, low-dispersion and low loss THz guiding.
abstract: Research on terahertz waveguides is experiencing a tremendous growth due to their importance for compact and robust THz systems. However, designing compact, broadband, mechanically stable and environmentally shielded THz waveguides is still a challenge due to high losses of both metals and dielectrics in this frequency range. Here we report on a novel twist on the classical tube waveguide where we deliberately introduce a thick and highly lossy cladding layer. By this we attenuate the field in the cladding and thus prevent interference with the core field. This mechanism breaks the well-known ARROW guiding mechanism, and as a result, extremely broad bandwidth and low dispersion can be achieved with a very simple design. Since the main part of the field propagates inside the air-core, the propagation loss is still kept at a very low level. Simulations, analytical modelling and experiments verify our findings. The proposed THz waveguide is robust, insensitive to external perturbation and easy to handle, and thus the design represents a significant advance of the field of THz dielectric waveguides suitable for the 0.3-1 THz band which in the future will be important for ultrafast wireless communication systems.
authors.affiliation: DTU Fotonik - Department of Photonics Engineering, Technical University of Denmark, Dk-2800 Kongens Lyngby, Denmark.
authors.forename: Hualong
authors.initials: H
authors.lastname: Bao
authors.affiliation: DTU Fotonik - Department of Photonics Engineering, Technical University of Denmark, Dk-2800 Kongens Lyngby, Denmark.
authors.forename: Kristian
authors.initials: K
authors.lastname: Nielsen
authors.affiliation: DTU Fotonik - Department of Photonics Engineering, Technical University of Denmark, Dk-2800 Kongens Lyngby, Denmark.
authors.forename: Ole
authors.initials: O
authors.lastname: Bang
authors.affiliation: DTU Fotonik - Department of Photonics Engineering, Technical University of Denmark, Dk-2800 Kongens Lyngby, Denmark.
authors.forename: Peter Uhd
authors.initials: PU
authors.lastname: Jepsen