Fabrication technology of photonic nanostructures with high precision is crucial for exploring interesting optical phenomena in photonic nanostructures, controlling the light-matter interaction, and realizing photonic and quantum devices utilizing them. We are promoting technological development to realize high-quality semiconductor-based photonic nanostructures, including photonic crystals and metasurfaces. Photonic crystals, which are artificial optical materials with a periodic refractive index structure that is about the wavelength of light, are one of the important platforms for nanophotonics. Besides, we aim to contribute to the advancement of quantum technology by developing nanofabrication technology for diamonds, Furthermore, we are also trying to develop nanofabrication technologies for various difficult-to-fabricate functional materials such as magneto-optical materials. We believe these fabrication technologies would open up a new paradigm of nanophotonics.

Using photonic nanostructures containing emitters such as quantum dots, we are pursuing the fundamental physic of light-matter interactions in photonic nanostructures toward future applications. Harnessing cavity quantum electrodynamics (CQED) effects, we develop highly efficient single-photon sources and quantum interfaces. Our research interests include the development of integrated quantum photonic circuits, where many quantum photonic devices are densely integrated on a chip. We are also interested in various types of angular momenta that photons can carry. In nanophotonic structures, a photonic analog of spin-orbit interaction can take place, which induces exotic optical phenomena. We not only pursue the fundamental study but also aim to realize unique nanophotonic devices based on the optical spin-orbit interaction, which include spin-photon interfaces, unidirectional light-emitting devices, and so on.

Topological photonics, which is an emerging field in photonics, is one of the research topics in our group. The concept of topology can provide a novel route for realizing optical devices with unprecedented functionalities. We are developing semiconductor-based topological nanophotonics based on our photonic crystal technology. We have demonstrated the world-first topological nanocavity laser. We have also proposed topological slow-light waveguides and have demonstrated them in semiconductor platforms for the first time. Our research also interests include synthetic dimension photonics, non-Hermitian photonics, and optical skyrmion and its applications.