Spin Hall effect of transmitted light through α-Li₃N-type topological semimetals

Abstract

The spin Hall effect of light occurring in topological semimetals provides unprecedented opportunities to exploit novel photonic properties and applications. In particular, pristine α-Li3N-type crystal has recently been predicted to...

Two-dimensional natural hyperbolic materials: from polaritons modulation to applications

“…To exploit more natural HMs and activate their hyperbolicity in a wider spectral range, it is necessary to attempt more approaches (being crucial to the onset frequency of hyperbolicity and the permittivity 93,151–154 ) to modify the electric structures and energy bands of anisotropic layered crystals. The potential approaches include but are not limited to controlling the temperature, 37 straining, 10 doping, 53 photoexcitation, 155 and external stimuli to the dielectric environment of HMs, 49 etc .…”

“…The transverse-electric (TE) and TM polarized waves can coexist in a HM. For a uniaxial medium, nontrivial solutions to eqn (9) yield the dispersion relation as (10) According to eqn (10), the IFS of TE wave takes the form of a sphere. However, the IFS of TM wave is an unbounded hyperboloid that can support high-k waves if the signs of two components of are opposite (εxx•εzz < 0).…”

“…According to eqn (10), the IFS of a TE wave takes the form of a sphere. However, the IFS of a TM wave is an unbounded hyperboloid that can support high-k waves if the signs of two components of ε are opposite (ε xx •ε zz < 0).…”

“…In particular, recent advances in the studies of high-quality, atomically thin van der Waals (vdW) crystals have been igniting tremendous enthusiasm for exploring novel 2D natural hyperbolic materials (HMs, also known as indefinite media). [7][8][9][10][11] Natural HMs are a special type of anisotropic media, and they are characterized by effective permittivity tensors where the principal components of the electric or magnetic fields have opposite signs. Therefore, the isofrequency surface (IFS) of transverse-magnetic (TM) polarized waves in HMs takes the form of an open hyperboloid.…”

Giant photonic spin Hall effect induced by hyperbolic shear polaritons

“…[6][7][8][9][10] Unfortunately, the PSHE is typically very weak and the spin-dependent displacements are always at the subwavelength scale, severely inhibiting its practical applications. 11,12 Until now, even if many strategies including polarization control, 13 anisotropic impedance mismatching, 14 constructing surface plasmonic platform 15 and various metastructures [16][17][18] have been proposed to enhance the PSHE, the largest photonic spin Hall shifts achieved by these methods are only hundreds of times of the incident wavelength. Besides, the element materials in most of the previously reported modulation methods preserve the time-reversal symmetry such that the Hall conductivity (equivalently the off-diagonal permittivity element) is generally zero.…”