Published papers

Slow light waveguides are advantageous for implementing high-performance single-photon sources required for scalable operation of integrated quantum photonic circuits (IQPCs), though such waveguides are known to suffer from propagation loss due to backscattering. A way to overcome the drawback is to use topological photonics, in which robust waveguiding in topologically-protected optical modes has recently been demonstrated. Here, single-photon sources are reported using single quantum dots (QDs) embedded in topological slow light waveguides based on valley photonic crystals. Purcell-enhanced single-photon emission is demonstrated from a QD into a topological slow light mode with a group index over 20 and its robust propagation even under the presence of sharp bends. These results pave the way for the realization of robust and high-performance single-photon sources indispensable for IQPCs.

We experimentally demonstrate on-chip optical skyrmionic beam generators. Skyrmionic beams with tailored skyrmion numbers were generated from single silicon mi-crorings diffracting two beams whose spin and orbital angular momenta were controlled via optical spin-orbit coupling.

We experimentally demonstrate on-chip optical skyrmionic beam generators. Skyrmionic beams with tailored skyrmion numbers were generated from single silicon microrings diffracting two beams whose spin and orbital angular momenta were controlled via optical spin-orbit coupling.

We design quantum-dot single-photon sources based on a defect-based photonic crystal cavity on a SiN waveguide with >90% efficiency. The defect region secures distance between etched airholes and quantum dots, expected to improve photon indistinguishability.

We design quantum-dot single-photon sources based on a defect-based photonic crystal cavity on a SiN waveguide with >90% efficiency. The defect region secures distance between etched airholes and quantum dots, expected to improve photon indistinguishability.

We design a quantum-dot single-photon source with a defect-based photonic crystal cavity on a SiN waveguide that subdues crosstalk from resonant excitation and has >90% coupling efficiency. It is expected to efficiently generate single photons with high purity and indistinguishability for scalable integrated quantum photonics.

We design an all-dielectric metasurface exhibiting giant enhancement of magneto-optical Faraday rotation and high light transmission. A 760-times larger Faraday rotation than that in the unprocessed host material of the same thickness was numerically observed.

We design an all-dielectric metasurface exhibiting giant enhancement of magneto-optical Faraday rotation and high light transmission. A 760-times larger Faraday rotation than that in the unprocessed host material of the same thickness was numerically observed.

We propose and numerically demonstrate an integrated non-Hermitian optomechanical system capable of exceptional-point encirclement in a deterministic manner. The proposed scheme opens a way for investigating non-Hermitian optomechanics on chip.

We propose and numerically demonstrate an integrated nonHermitian optomechanical system capable of exceptionalpoint encirclement in a deterministic manner. The proposed scheme opens a way for investigating nonHermitian optomechanics on chip.

We demonstrated the fabrication of silicon valley photonic crystal structures with triangular air holes by using photolithography for the first time. The mask patterns we newly designed enable the formation of triangular air holes with reasonably high accuracy. This is an important step toward CMOS-compatible topological nanophotonics.

We fabricate a membrane distributed-reflector lasers with a Si waveguide by using micro-transfer printing, achieving a low threshold current of 1.1-3.7 mA in a temperature range of 25-80 C and good optical coupling between the laser output and 220-nm-thick Si waveguides.

We will discuss the hybrid integration of micro/nanoscale light sources on silicon photonics circuits with transfer printing, which is based on pick-and-place assembly using a viscoelastic stamp. Various light sources including quantum-dot single-photon sources are readily and flexibly integrated on silicon with high positioning accuracy.

We propose a scheme to generate intrinsically chiral modes via non-Hermitian backscattering caused by the loss-induced imaginary coupling between the two orthogonal linearly polarized dipole modes in the H1 photonic crystal cavity.

We propose a scheme to generate intrinsically chiral modes via non-Hermitian backscattering caused by the loss-induced imaginary coupling between the two orthogonal linearly polarized dipole modes in the H1 photonic crystal cavity.

We fabricate directly modulated membrane distributed reflector lasers on a Si waveguide by using the micro-transfer printing. A low threshold current of 1.2 mA and good optical coupling between the laser output and 220-nm-thick Si waveguides are achieved. 50-Gbit/s NRZ signal modulation is also demonstrated.

Topological photonic crystals made of compound semiconductors are a fascinating platform to develop topological nanophotonic devices with active functionalities. In this contribution, will discuss recent progress in IIIV-semiconductor topological nanophotonics incorporating optical gain media and quantum emitters. We will review several ways to realize topological nanocavities and topological slow light waveguides, both of which can significantly enhance light-matter interactions with embedded light emitters. These photonic structures enable the realization of topological nano/microlasers and quantum light sources capable of robust operation.

We report a topologically-protected single photon source in a slow light waveguide based on valley photonic crystals. Purcell-enhanced single photon generation from a quantum dot and its robust propagation in the topological waveguide are demonstrated.