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| @Curriculum Vitae |
y Education z |
| Bachelor of Science ( Tokyo University ), Master of Science ( Tokyo University ), Doctor of Science, ( Tokyo University , 2000) |
y Academic Experience z |
| Postdoctoral Researcher (Frontier Research System, RIKEN)
Postdoctoral Researcher (CREST, JST),
Research Associate ( Wakayama Universityj
Associate Professor(Tokyo Medical and Dental University, current position ,since 2007j
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| Research interests |
Theory of quantum dynamics (particularly, quantum optics and optical response of condensed matter) |
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Driving. Window shopping at interior shops |
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| @Introduction of the project |
| @@Light pulses interact very weakly with the environmental degrees of freedom,
and therefore can preserve quantum coherence for a much longer time than other
physical systems. Particularly, the number-state photon pulses (single photon
pulse, entangled photon pairs, etc) are regarded to be the best candidate to
implement the quantum information processing. Thus, control of photon by photon
(more precisely, control of quantum state of photons using nonlinear optical
effects) has become one of the most attractive research objectives in the modern
photonics technology. A conventional belief is that strong input light fields
are indispensable to obtain significant nonlinear optical effects, and therefore
that the nonlinear effects induced by extremely weak input fields at the single-photon
level are negligibly small. However, the absorption saturation occurring at optical
systems having discrete quantum levels (atoms, molecules, quantum dots, etc.)
can yield giant nonlinear optical effects sensitive to individual photons. Therefore,
by placing such optical media inside of a resonator and thus attaining effective
interaction between input photons and the optical media, significant nonlinear
optical effects can be expected even by weak input of only several photons. Furthermore,
the optical properties of the media (resonance energy, etc) can be variable in
time by external factors such as laser irradiation. The principal objective of
this project is to develop theoretically the control method of number-state photon
pulses, using the dynamic optical media placed inside of an optical resonator.
Conventionally, the quantum state of a photon is characterized only by discrete
quantum numbers such as the photon number and the polarization. However, in the
light of nonlinear optics in which the field amplitude plays a key role, the
spatial forms of photonic pulses must be rigorously taken into account in theory.
(For example, absorption of a photon by the optical media is sensitive to the
spatial form of the photonic pulse. The deformation of photonic pulse shapes,
which is an inevitable consequence of strong interaction between photons and
optical media, degrades the coherence of photons and serves as an obstacle in
device applications.) In this project, based on a formalism in which (i) the
photon field is treated rigorously as a multimode continuum, and (ii) both the
photon field and the optical media are treated quantum-mechanically, we construct
a quantum-optics theory which enables the spatio-temporal description of photons,
and develop a novel method of photon control including photonic pulse shape.
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Figure caption
Schematic view of photon control.
(a) By placing a few-level quantum system inside of a cavity, we can obtain strong interaction between photons, applicable to control of individual photons D
(b) By application of external fields (laser field), we can realize a dynamic optical system, which is useful to engineer the output photons. |
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