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RESEARCH FOCUS |
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Optoelectronic materials & devices, Semiconductor physics; Optical
spectroscopy; Nano-materials & Technology, etc. |
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Detailed
Research Interests |
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Our research theme exists
at the interface between optical physics and material science, i.e.
light-matter interaction. Besides the physical interest, potential
application is always our strong driving force for the research.
Current research activities will focus on but not limited to the
following topics. |
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I. Optical
Spectroscopic Characterization |
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Optical spectroscopy
provides a powerful tool for understanding the physical properties
of a wide range of condensed matters. The investigated materials
cover from the traditional inorganic semiconductors (bulk, quantum
dots, wires and wells), organic semiconductors to artificial
materials (organic/inorganic hybrid structures and composites). We
are interested in the investigation of electronic structures,
various elemental excitations and their dynamic process in
semiconductor structures; energy transfer; charge separation and
transport in various organic blends and organic/inorganic
composites. The clarification of the underlying physics is very
important for both fundamental physics interest and development of
optoelectronic devices.
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II.
Optoelectronic Devices |
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On the basis of
understanding the optical properties of a wide range of materials,
we will dedicate to develop useful optoelectronic devices. For
example, we will seek to utilize wide bandgap material systems to
develop surface emitting lasers for the important blue-green to
ultraviolet wavelength range. Taking advantage of the unique
material properties inherent to wide bandgap materials, especially
high excitonic oscillator strength and high exciton binding energy,
it is expected to directly generate solid state lasers in blue-green
to UV wavelength range with high power and high beam quality for a
wide range of applications. The relevant material processing
techniques will be further developed to form high quality
microcavity in the strong coupling regime, which will makes it
possible to experimentally explore the exciting physics of Cavity
Quantum Electrodynamics and new concept devices-room temperature
polariton lasers.
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III. Plasmonics
Optics |
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In practical light emitting
devices, the overall efficiency depends on not only the internal
quantum efficiency of the active materials but also on the external
conditions. Photonic crystals and surface plasmon coupling are two
effective approaches to improving the light extraction rate from the
active materials. Surface plasmon polaritons are created via the
coupling of light to the motion of the conduction electrons at a
metallic interface. Enhanced emission from the surface plasmons is
possible due to the large density of states in their dispersion
diagram. Excitation of surface plasmon polaritons within the metal
at nano-scale can create strong local optical fields, which can be
exploited for numerous applications, such as single-molecule
fluorescence, surface-enhanced second harmonic generation and
surface-enhanced Raman scattering etc. Photonic devices at nano-scale
are possible because light can be confined this way to dimensions
below the diffraction limit of light. More over, it has been shown
that the hybrid metal/dielectric layers with particular geometry
display interesting transmission properties for electromagnetic
waves including wavelength selectivity, particular emission angle
distribution and even negative refractive index. Therefore the
related research is expected to have great impact on photonics and
biomedical detection.
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IV.
Applications
of Photonics |
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The combination of
photonics and biotechnology may provide some of the most exciting
scientific and commercial prospects. Successful commercial examples
include corrective eye surgery and dentistry by lasers etc.. New
applications have also been found for lasers in biomedical imaging,
optical tomography and optical biochips which use light to excite
specially designed fluorescent chemicals that can reveal important
features about each cell such as how it responds to a drug or
whether or not it is diseased. However, there are still a lot
remained unknown in the interaction between photons and
bio-molecules, and big space exist in the use of light for both
diagnostic purposes and as a powerful tool for manipulating material
on cellular and sub-cellular length scales. We are interested in
intra- and inter biomolecules-photo-driven biological processes with
the aim of understanding how nature efficiently converts solar
energy to perform critical biological functions. The tools related
to the research include FRET based probes, anisotropic spectroscopy,
surface-enhanced Raman scattering, time-resolved fluorescence and
absorption, selectively excited fluorescence etc. The combination of
these techniques and nano materials (e.g. carbon nanotubes and
plasmon resonant nano-metals etc.) can be used to generate nanoscale
biosensors. Such research will be undertaken by synergic cooperating
with chemists and biologists.
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Copyright © Optoelectronics Lab (2010) |