IAS Newsletter - May 2014 - page 6-7

Knowledge Corner
IAS has just revamped and launched its new website in early February 2014, making a
new digital home for IAS news and information. This is the second revamp since the last
one conducted back in 2010.
Considering from the users’ perspectives, the website’s structure, layout and functions
are further reviewed and improved. Here are the major enhancements.
IAS Community
Easy navigation
Web pages are now much clearly organized with easy
navigation everywhere on the website. Upcoming
functions such as programs, conferences, lectures and
seminars are placed on the front page. Latest news that
features IAS people and development is also listed with
attractive photos. IAS Channel, being one of the greatest
assets for the benefit of the HKUST community and
beyond, is put up on the top for handy access.
Eye-catching photos and website style
The use of more eye-catching photos and graphics has
added much color to the overall style of the website.
Users can also feel the dynamics and vitality of IAS and
understand the operation better with more lively
functions photos.
Functions improvement
Search function for information such as events is now fully
functional with a freshly established website database.
The website also facilitates tablet or smart phone viewing
to catch the wave of the latest trends of science and
Information sharing
To make this a comprehensive pool, more relevant
information is included. New sessions such as History &
Development, Photo Gallery, and Facilities are added.
Check out more on
Website Revamp:
A New Digital Home
Selected as the cover
story of Nature
Photonics, HKUST
research group
showed that “optical
tractor beam” (i.e.
using light to pull an
object) is possible.
There are currently a lot of research activities worldwide aimed at creating a new generation of materials and structures
that can manipulate light and sound and use these materials to realize superior wave manipulation functionalities that go
beyond the limit of normal materials. These “wave functional materials” include photonic crystals, phononic crystals,
metamaterials and plasmonic structures. They can make what seems to be impossible possible and has the potential to
bring future technology closer to reality.
The simplest example of a wave functional material would be ordinary lenses made of glass, which by bending light in a
simple way have become the key component of optical instruments such as microscopes and telescopes. Ordinary lenses
are very simple: they are made of a single material (glass) with a very simple structure (crafted surfaces). Advances in
theory and fabrication technology have allowed us to make multi-component composites with many more degrees of
freedom to control waves. We can now design and fabricate new materials composing of an array of engineered
resonating units arranged in a periodic structure with a shape that is optimized for a specific functionality. If the resonant
units and the lattice period are much smaller than the wavelength, the material is called a "metamaterial". If the lattice
period is close to the wavelength, the material is called a “photonic crystal”. If the resonant units are made of nano-scale
metallic structures that are resonant at optical frequencies, the material is called a “plasmonic structure”. These materials
can manipulate waves in a way that traditional optical elements such as a glass lens cannot. They can control the density
of radiation modes (giving more efficient light emitting devices, thermal radiation control), bend light in unusual ways
(giving negative refraction, super-resolution, efficient antennae), modify scattering and absorption properties (giving
science-fiction type effects such as invisibility, stealth, noise reduction, superior light harvesting), confine and guide waves
(giving optical chips, superior wave guides, highly directional
sources) and increase local field strength (giving
ultra-sensitive sensors, light manipulation of matter, strong
non-linear effects).
HKUST has a team that has actively participated in this
exciting development by introducing new concepts in this
field such as photonic quasi-crystals, negative dynamic mass,
acoustic metamaterials, remote cloaking, illusion optics and
optical pulling force. The research in this area is supported
by the Hong Kong Research Grants Council through the
Areas of Excellence Project "Novel Wave Functional Materials
for Manipulating Light and Sound". The research team
consists of 8 faculties from HKUST and partners from Hong
Kong Baptist University, the Chinese University of Hong
Kong, City University of Hong Kong and the Polytechnic
University of Hong Kong.
The figure shows such a prism shaped photonic crystal comprising
a square array of Si rods 25 μm high. The sample is made by Prof.
W.Y. Tam’s group using electron-beam lithography and samples like
this will behave as if it has a zero-refractive index. Zero-index
material is a special kind of wave-functional material. In a specific
frequency range, zero-index materials are “more empty than
vacuum” for light travelling inside it.
Prof Che Ting Chan
, Executive Director of IAS and Chair Professor of Physics
MAY 2014
MAY 2014
1,2-3,4-5 8-9,10-11,12-13,14-15,16-17,18-19,20
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