非対称型ダブルバーメタマテリアルを用いたプラズモニックナノ共振器

要約のみTohoku University金森義明課

High Transmission in 120-degree Sharp Bends of Inversion-symmetric and Inversion-asymmetric Photonic Crystal Waveguides

Bending loss is one of the serious problems for constructing nanophotonic integrated circuits. Recently, many works reported that valley photonic crystals (VPhCs) enable significantly high transmission via 120-degree sharp bends. However, it is unclear whether the high bend-transmission results directly from the valley-photonic effects, which are based on the breaking of inversion symmetry. In this study, we conduct a series of comparative numerical and experimental investigations of bend-transmission in various triangular PhCs with and without inversion symmetry and reveal that the high bend-transmission is solely determined by the domain-wall configuration and independent of the existence of the inversion symmetry. Preliminary analysis of the polarization distribution indicates that high bend-transmissions are closely related to the appearance of local topological polarization singularities near the bending section. Our work demonstrates that high transmission can be achieved in a much wider family of PhC waveguides, which may provide novel designs for low-loss nanophotonic integrated circuits with enhanced flexibility and a new understanding of the nature of valley-photonicsComment: 15 pages, 7 figures, and 1 table & Supplementary information (18 pages, 15 figures and 1 table). Submitted to Nature Communicatio

Lifetime reduction of a quantum emitter with quasiperiodic metamaterials

Enhancement of light-matter interaction of a quantum emitter with subwavelength quasiperiodic metamaterials is proposed and demonstrated. The quasiperiodic metamaterials consist of subwavelength metal-dielectric multilayers, which are arranged into a Fibonacci lattice. The influence of Fibonacci metamaterials (FM) on the dipole emission is analyzed with a semiclassical model. The local density of states near FM is evaluated and a characteristic mode in higher wave numbers is revealed; a strong enhancement of the decay rate was predicted. A lifetime measurement is carried out and a reduction of lifetime of quantum dots on the surface of FM is observed. The enhancement of light-matter interaction arises from the localized latticelike state inherent for self-similar quasiperiodic order

Radiation control with exceptional points in non-Hermitian plasmonic systems

In this paper, we introduce our research based on the singular eigenstates in EP. The first is formation of circular polarization eigenstates and the second is formation of Huygens dipoles at EPs. The studies introduced in this paper provide new photonic functionalities caused by the singular eigenstates at EP in NH systems