We conduct experimental research in quantum optics and quantum technologies using photons, quantum particles of light.
The concept of the photon is essential for understanding quantum phenomena such as black-body radiation and the photo-electric effect. In experimental studies, photons are an excellent tool to explore the quantum world due to their stability in an ordinary lab environment. They are also expected to play a significant role in quantum technologies including quantum computing, quantum cryptography, and quantum metrology.
Our primary goal is to gain an understanding of counter-intuitive quantum phenomena such as quantum entanglement and quantum fluctuations, and to apply them to the development of new quantum technologies. Our ongoing projects involve nonlinear optics with single photons, observing novel multi-photon interference, generating and detecting large-scale photonic entanglement, developing optical quantum gates, and precision quantum optical measurement and networking.
Organic materials with conjugated p-electrons have much interests because they are model compounds of low-dimensional systems. Moreover, they make higher order structures. For example, LH2 complex in bacterial photosynthesis (Left Figure) has a beautiful ring structure. A carbon nanotube can encapsulate other molecules (Center Figure). We are investigating ultrafast dynamics in the complex systems to find new optical functions.
We are developing
femtosecond
spectroscopies to measure ultrafast phenomena in the conjugated
p-electron systems. Using
tunable multi pulses, a proper state in the material can be selectively excited
by linear and nonlinear photoexcitation. The dynamics following the excitation
are measured using femtosecond absorption, fluorescence, and Raman
spectroscopies.
Left: Pigment-protein complex of photosynthesis, Center: Carbon nanotube
encapsulating molecule, Right: Equipment of laser spectroscopy