Kato Group

Nanoscale Quantum Photonics Laboratory, RIKEN


Our primary interest is in the development and engineering of photonic and optoelectronic devices that would allow for manipulation of quantum states, as well as understanding the underlying physics in the operation of such devices. We exploit state-of-the-art semiconductor processing technology to fabricate nanoscale devices and perform experiments that combine microspectroscopy with electronic techniques. Our current focus is on devices that utilize individual single-walled carbon nanotubes.

Introduction to single-walled carbon nanotubes

A sheet made of carbon atoms arranged in a honeycomb lattice is called a graphene sheet. Single-walled carbon nanotubes are made by rolling up such a graphene sheet into a tube. What's really interesting about single walled carbon nanotubes is that their electronic structure can become either semiconducting or metallic depending on how it is rolled up. Single-walled carbon nanotubes have diameters of only a few nanometers, but they can grow as long as a millimeter, making it fairly easy to fabricate devices with individual nanotubes.

Optical properties of carbon nanotubes

Carbon nanotubes have unique optical properties because of their one-dimensional structure.

Carbon nanotube optoelectronics

Semiconducting carbon nanotubes have direct bandgap, making them suitable for optoelectronic devices.

Carbon nanotube photonics

Integrating nanotube light emitters with photonic structures may open up possibilities for nanoscale optical circuits.