Backscattering-immune one-way surface magnetoplasmons at terahertz frequencies

Abstract

Surface magnetoplasmons (SMPs) in a basic physical model for the terahertz regime, which consists of a semi-infinite magnetized semiconductor with dielectric cladding terminated by a metal slab, are theoretically investigated. The dispersion properties of such SMPs are analyzed and examined in detail. It is shown that SMPs may follow three different kinds of dispersion diagrams, depending on the applied dc magnetic field intensity. Complete one-way propagation that operates within the band gap of the semiconductor is available for SMPs, and the one-way bandwidth reaches a maximum at a certain magnetic field intensity. Regular modes guided by the dielectric layer are also analyzed. These modes may cause the (complete) SMP one-way region to be compressed or even removed, but they can be suppressed by reducing the dielectric layer thickness. Owing to the mirror effect of the metal slab, one-way propagating and backscattering-immune basic SMPs can exhibit a larger propagation length than those sustained by a single dielectric-semiconductor interface.

Broadband one-way propagation and rainbow trapping of terahertz radiations

“…One-way EM mode of different type, which is based on surface plasmons (SPs) [12], has also been proposed [13]. It seems to be more attractive owing to its robustness in mechanism and simpleness in configuration [14][15][16].…”

“…Surface plasmons (SPs) sustained by the interface of plasmonic material and dielectric become nonreciprocal under an external dc magnetic field [17,18]. When the cyclotron frequency of electron (ω c ) in the plasmonic material is comparable with the plasma frequency, the SP asymptotic frequency differs remarkably in the forward and backward directions, making SP propagate unidirectionally within the interval between the two different asymptotic frequencies [13,15]. SPs in magnetized plasmonic material is generally referred to as surface magnetoplasmons (SMPs) [17].…”

“…Therefore, one-way SMPs is realizable at terahertz frequencies by using semiconductors [14]. In a semiconductor-dielectric-metal (SDM) layered structure, it was shown that one-way SMPs can be immune to backscattering, thus exhibiting the complete one-way propagation (COWP) [15,19].…”

One-way surface magnetoplasmon cavity and its application for nonreciprocal devices

“…which are the same as SMPs at a planar interface discussed in [17]. Within the one-way frequency range f −∞ < f < f +∞ , there only exists |+m modes, and SMPs can only circulate around the cavity anti-clockwise.…”

Unidirectional-propagating surface magnetoplasmon based on remanence and its application for subwavelength isolators

“…Surface plasmons, collective oscillations of charge-carriers in conductors or doped semiconductors, provide subwavelength confinement of optical field, and thus hold a great potential in minimizing the scale of optical systems [1][2][3]. Magnetoplasmons (MPs) are surface plasmons sustained at the interface between a dielectric and a magneto-optical material applied with a static external magnetic field [4][5][6]. Compared with surface plasmons, MPs can exhibit one-way propagation due to the breaking of the time reversal symmetry by the external magnetic field [7][8][9].…”