Gyroelectric properties of indium antimonide at terahertz frequencies

The behaviour of a magnetised semiconductor can be characterised by a permittivity tensor, which combines the ohmic and displacement currents. The frequency dependence of the permittivity tensor elements is described. A semiconductor that is magnetised transverse to the direction of propagation such that the microwave electric field is perpendicular to applied static magnetic field (i.e. a TM mode) is described by an effective permittivity, ε_eff. The variation of ε_eff of indium antimonide (ε_r =17.7) as a function of frequency up to the terahertz region is described. The reflection and transmission coefficients for oblique incidence on a simple dielectric and semiconductor interface have been derived and it can be shown that a reflectionless condition is achievable only at normal incidence. The frequency dependence of the complex reflection coefficient for normal incidence is presented and discussed