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AssigneeThe Regents of the University of California
InventorsAlexander Figotin, Ilya Vitebskiy
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An unidirectional gyrotropic photonic crystal allows electromagnetic wave propagation in a certain direction at a certain frequency and, at the same time, impedes electromagnetic wave propagation in the opposite direction. The electromagnetic wave with impeded propagation, called the “frozen mode”, ideally has zero group velocity and does not transfer the electromagnetic energy. A unidirectional gyrotropic photonic crystal is a periodic composite, incorporating a component displaying Faraday rotation. The property of unidirectionality can be achieved in gyrotropic photonic crystals by proper choices of constituents and their space arrangement. The invention can be used to enhance the capability and performance of microwave, millimeter wave, and submillimeter wave antennas, delay lines, nonlinear and nonreciprocal elements. It can also be used in integrated microwave circuitry.
A photonic crystal with bulk spectral asymmetry comprising a plurality of at least two homogeneous constitutive components forming a periodic array, which homogeneous constitutive components are substantially lossless at an electromagnetic frequency of interest, at least one of the two homogeneous constitutive components having a spontaneous magnetic order and/or an induced magnetic order from an applied external magnetic field, the periodic array having a composition and geometry so that the array displays strong bulk spectral asymmetry and, at least at one particular frequency Ω, it displays electromagnetic unidirectionality.
A photonic crystal comprising a plurality of at least two homogeneous constitutive components forming a periodic array, which homogeneous constitutive components are substantially lossless at an electromagnetic frequency of interest, at least one of the two homogeneous constitutive components being a ferromagnet or a ferrite, so that the array is electromagnetic unidirectional for at least one particular frequency and at least one particular direction of propagation.
An unidirectional slab device with frequency and directional selectivity comprised of an unidirectional photonic crystal bounded by two plane faces, each of which is perpendicular to a Z-direction associated with a frozen mode frequency Ω, such that a first wave packet of frequency Ω and normal incidence impinging on one plane face is transmitted through the photonic crystal, while a second wave packet of the same frequency Ω and in the opposite direction of propagation impinging on the opposite face is trapped inside the slab device where it accumulates or is processed.
Dependencies are inferred from the claim text.