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تسجيل مستخدم جديدA Topology-Controlled Photonic Cavity Based on the Near-Conservation of the Valley Degree of Freedom
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We demonstrate a novel path to localizing topologically-nontrivial photonic edge modes along their propagation direction. Our approach is based on the near-conservation of the photonic valley degree of freedom associated with valley-polarized edge states. When the edge state is reflected from a judiciously oriented mirror, its optical energy is localized at the mirror surface because of an extended time delay required for valley-index-flipping. The degree of energy localization at the resulting topology-controlled photonic cavity (TCPC) is determined by the valley-flipping time, which is in turn controlled by the geometry of the mirror. Intuitive analytic descriptions of the leaky and closed TCPCs are presented, and two specific designs--one for the microwave and the other for the optical spectral ranges--are proposed.
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