One-way helical electromagnetic wave propagation supported by magnetized plasma

Abstract

In this paper we reveal the presence of photonic one-way helical surface states in a simple natural system- magnetized plasma. The application of an external magnetic field to a bulk plasma body not only breaks time-reversal-symmetry but also leads to separation of Equi-Frequency Contour surfaces (EFCs) to form topologically nontrivial gaps in k space. Interestingly, these EFCs support topologically protected surface states. We numerically investigate an interface between magnetized plasma, using a realistic model for parameter dispersion, and vacuum, to confirm the existence of one-way scatter-immune helical surface states. Unlike previous proposals for achieving photonic one-way propagation, our scheme does not require the use of artificial structures and should therefore be simple to implement experimentally.

Photonic Weyl points due to broken time-reversal symmetry in magnetized semiconductor

“…They may enable multiple striking topological features such as Majorana type edge states and zero mode 22 , which do not exist in inversion symmetry breaking systems. Although there have been theoretical proposals on implementation of Weyl degeneracies by applying external magnetic fields on finely designed photonic crystals 16,31 , very few of them are easily realizable in experiment due to the challenge in three-dimensional structuring of magnetic materials 32,33 . Interestingly, it was recently theoretically proposed that plasma, the fourth fundamental state of natural matter 34,35 , can support Weyl degeneracies under external magnetic fields 19 , as well as nonreciprocal wave transport [36][37][38] . Since there is no structuring involved, this represents a facile and tunable approach for achieving photonic Weyl degeneracies arising from time-reversal symmetry breaking.…”

Size and host-medium effects on topologically protected surface states in bianisotropic three-dimensional optical waveguides

“…Electronic properties of topological phases of matter, including topological insulators, have been under intensive investigation in the past decades [1][2][3][4], and this culminated in the Nobel prize in Physics in 2016 being awarded to D. J. Thouless, F. D. M. Haldane and J. M. Kosterlitz "for theoretical discoveries of topological phase transitions and topological phases of matter" [5]. In the meantime, this intensive interest in topological phases of matter has also stimulated widespread studies on complex topology of dispersion relations of photonic crystals and metamaterials, leading to the appearance of topological photonics [6][7][8][9][10][11][12][13][14][15][18][19][20][21], a new and vibrant area in nanophotonics and nanooptics. Examples of such photonic materials include bi-anisotropic materials [7], magnetized cold plasma [8,9] or planar photonics crystals [10][11][12][13][14][15].…”

Berry Phase, Berry Connection, and Chern Number for a Continuum Bianisotropic Material From a Classical Electromagnetics Perspective

“…If the bias is turned off (ε 12 = 0), the material is reciprocal (ε 12 = 0), the longitudinal electric field is zero so that the field does not rotate as described above, the eigenfunctions are real-valued, and all Berry quantities vanish (A = F = 0). The Berry connection and phase are defined solely in terms of the envelope of the eigenmodes, (47); the propagation factor e ik·r is not involved in computing the Berry phase. As described in Sec.…”