2019/06/07 by Farshad Yazdi, Dmitry Oshmarin, Yazdi, Farshad +9
Engineering · Materials Science · Physics and Astronomy · #Applied Physics (physics.app-ph) #FOS: Physical sciences #Gyrotron and Vacuum Electronics Research #Metamaterials and Metasurfaces Applications #Microwave Engineering and Waveguides #Quantum Mechanics and Non-Hermitian Physics
paper · pdf · doi:10.48550/arxiv.1906.03331
openalex publication_date 2019/06/07 · openalex created_date 2022/07/28 · openalex updated_date 2026/07/28
We show the physical realization and experimental demonstration of an\nexceptional point of 6th order degeneracy in a triple ladder (or three-way)\nmicrowave waveguide realized using three coupled microstrips on a grounded\ndielectric substrate. This threeway waveguide supports six Bloch eigenmodes and\nall coalesce onto a degenerate single eigenmode at a given frequency. The\nthree-way waveguide is gainless, and this exceptional point is associated to a\nvanishing group velocity and its multiple derivatives. Indeed the\nwavenumber-frequency dispersion diagram, that we call 6th order degenerate band\nedge (6DBE) has six coalescing branches. We provide the experimental\nverification of a 6th order exceptional point by evaluating the degenerate\nwavenumber-frequency dispersion diagram from the measurement of scattering\nparameters of a six-port unit cell. We also show the resonant behavior of a\ncavity made of the three-way waveguide with finite length. The unique\nproperties of 6DBE can be exploited in designing innovative high-Q resonators,\noscillators, filters, and pulse shaping devices.\n