Slab waveguides with anisotropic core composed of low-dimensional quantum structures. Anisotropy comes from spatial composition of embedded structures and leads to LHM properties (Ref. 4): (a) core composed of quantum wells; (b) core composed of coupled quantum dots.
The criterion for LHM operation is that the perpendicular term of electrical permittivity tensor of the waveguide core is negative and its parallel term is positive (Ref. 4). While the parallel part is always positive, the perpendicular part of permittivity tensor of the waveguide core based on QW inclusions is depicted. Transparent bar highlights the LHM region: (a) passive device; (b) active device.
The considerable advantage of semiconductor devices is their sensitivity to applied voltage. This external trigger changes the configuration of internal quantum levels, leading the voltage controllability of material regime. Transparent bar highlights the LHM region.
Schematics of metamaterial comprised of coupled QDs. The required anisotropy (Ref. 4) comes from spatial organization of QDs. Dipole selection rules define the orientation of the orbital of spherical QD. Horizontally polarized incident light (a) encounters negligibly coupled QDs, while vertical polarization (b) interacts with highly coupled structure.
Simulation of imaginary (top) and real (bottom) parts of electric permittivity of the system of coupled QDs. The electric permittivity curves represent the anisotropy of the tensor. Transparent bar highlights the Podolskiy-Narimanov criterion ( and ) hence, the region of LHM.
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