[10p-N404-1~14] 4.1 Plasmonics and Nanophotonics

▲ [10p-N404-5] One-side excited one-way modes in nonreciprocal waveguides

〇Tianji Liu¹, Yasutomo Ota^2,3, Satoshi Iwamoto^1,3,4 (1.RCAST, Univ. of Tokyo, 2.APPI, Keio Univ., 3.NanoQuine, Univ. of Tokyo, 4.IIS, Univ. of Tokyo)

Keywords:Magneto-optical effect, Unidirectionality, Janus Dipole

Manipulation of the flow of light is one of the key issues in photonics. Unidirectional and robust photonic states are found in photonic structures with nontrivial band topologies or strong nonreciprocity, which are promising for on-chip integrated photonics. In addition, using phenomena like spin-momentum locking, circular dipole (CD) sources could excite unidirectional and robust surface modes at interfaces of nearby photonic structures. Besides CD, the recently proposed Janus dipole (JD) source, which is composed of ±p/2 out-of-phase orthogonal electric dipole (p) and magnetic dipole (m), enables switchable one-side excited surface modes. The combination of unidirectional states and polarization-engineered dipole sources would bring new research opportunities in the manipulation of near-field directionality.
Here we propose a way to realize one-side excited one-way surface modes in nonreciprocal metal-dielectric-metal waveguides, which includes the one-side excitation by a JD source and the one-way photonic states in epsilon-near-zero (ENZ) magneto-optical (MO) waveguides. Our results not only enrich the understanding of near-field directionality but also pave the way toward novel applications for on-chip integrated photonics.