Kazuhiro Kuruma 교수

We demonstrate optical coupling between a single tin-vacancy (SnV) center in diamond and a free-standing photonic crystal nanobeam cavity. The cavities are fabricated using quasi-isotropic etching and feature experimentally measured quality factors as high as ∼11 000. We investigate the dependence of a single SnV center's emission by controlling the cavity wavelength using a laser-induced gas desorption technique. Under resonance conditions, we observe an intensity enhancement of the SnV emissio

We demonstrate precise and quick detection of the positions of quantum dots (QDs) embedded in two-dimensional photonic crystal nanocavities. We apply this technique to investigate the QD position dependence of the optical coupling between the QD and the nanocavity. We use a scanning electron microscope (SEM) operating at a low acceleration voltage to detect surface bumps induced by the QDs buried underneath. This enables QD detection with a sub-10 nm precision. We then experimentally measure the

Abstract 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

We report time domain observation of vacuum Rabi oscillations in a single quantum dot strongly coupled to a nanocavity under incoherent optical carrier injection. We realize a photonic crystal nanocavity with a very high quality factor of $>80\phantom{\rule{0.16em}{0ex}}000$ and employ it to clearly resolve the ultrafast vacuum Rabi oscillations by simple photoluminescence-based experiments. We found that the time domain vacuum Rabi oscillations were largely modified when changing the pump wa

We demonstrate two-dimensional photonic crystal cavities operating at telecommunication wavelengths in a single-crystal diamond membrane. We use a high-optical-quality and thin (~ 300 nm) diamond membrane, supported by a polycrystalline diamond frame, to realize fully suspended two-dimensional photonic crystal cavities with a high theoretical quality factor of ~ $8\times10^6$ and a relatively small mode volume of ~2$({\lambda}/n)^3$. The cavities are fabricated in the membrane using electron-bea

Diamond color centers are promising candidates for optically addressable quantum memories, which motivates the development of efficient photonic interfaces, often using nanophotonic cavities with narrow spectral line widths and small mode volumes. However, they require perfect spectral and spatial overlap between the cavity mode and quantum emitter, which is challenging. This is especially true for solid-state quantum emitters that are often randomly positioned and suffer from inhomogeneous broa

The ability to control phonons in solids is key for diverse quantum applications, ranging from quantum information processing to sensing. Often, phonons are sources of noise and decoherence, since they can interact with a variety of solid-state quantum systems. To mitigate this, quantum systems typically operate at milli-Kelvin temperatures to reduce the number of thermal phonons. Here we demonstrate an alternative approach that relies on engineering phononic density of states, drawing inspirati

The development of microscopy and spectroscopy techniques to characterize and study two-dimensional (2D) materials is key for diverse optoelectronic and biomedical applications. Spontaneous Raman microscopy is one of the most employed techniques due to its simple and non-destructive procedure, though it relies on weak Raman signals, which can limit its imaging speed and image details as well as spectroscopic applications. Here, we report vibrational imaging with stimulated Raman scattering (SRS)

We demonstrate coupling of a tin-vacancy (SnV) center and a photonic crystal nanobeam cavity in diamond. We observed a 12-hold intensity enhancement of SnV emission and a 16-hold reduction in its lifetime under resonance conditions.