Department+of+Physics
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Biomimetic reflective display technology developed
Professor Shin Jung Hoon
The bright colors of a rainbow or a peacock are produced by the reflection and interference of light in transparent periodic structures, producing what is called a structural color. These colors are very bright and change according to the viewing angle. On the other hand, the wings of a morpho-butterfly also have structural colors but are predominantly blue over a wide range of angles. This is because the unique structure of the morpho-butterfly’s wings contains both order and chaos.
Professor Shin Jung Hoon’s team from the Department of Physics and the Graduate School of Nanoscience and Technology at KAIST produced a display that mimics the structure of the morpho-butterfly’s wings using glass beads.
This research successfully produced a reflective display (one that reflects external light to project images), which could be used to make very bright displays with low energy consumption. This technology can also be used to make anti-counterfeit bills, as well as coating materials for mobile phones and wallets.
The structure of the morpho-butterfly’s wings seems to be in periodic order at the 1-micrometer level, but contains disorder at the 100-nanometer level. So far, no one had succeeded in reproducing a structure with both order and disorder at the nanometer level.
Professor Shin’s team randomly aligned differently sized glass beads of a few hundred nanometers to create chaos and placed a thin periodic film on top of it using the semiconductor deposition method, thereby creating the morpho-butterfly-like structure over a large area.
This new development produced better color and brightness than the morpho-butterfly wing and even exhibited less color change according to angle. The team sealed the film in thin plastic, which helped to maintain the superior properties whilst making it more firm and paper-like.
Professor Shin emphasized that the results were an exemplary success in the field of biomimetics and that structural colors could have other applications in sensors and fashion, for example.
The results were first introduced on May 3rd in Nature as one of the Research Highlights and will be published in the online version of the material science magazine, Advanced Materials.
This research was jointly conducted by Professor Shin Jung Hoon (Department of Physics / Graduate School of Nanoscience and Technology at KAIST), Professor Park NamKyoo (Department of Electrical and Computer Engineering at Seoul National University), and Samsung Advanced Institute of Technology. The funding was provided by the National Research Foundation of Korea and the Ministry of Education, Science and Technology as part of the World Class University (WCU) project.
Figure 2. The biomimetic film can express many different colors
Figure 3. The biomimetic diplay and a morpho-butterfly
2012.05.07 View 15874 -
Attosecond pulses measure ultrafast photoionization processes by Laser Focus World, April 12, 2012
Laser Focus World, a monthly magazine published since 1965 that covers news and business developments on laser, photonics, and optoelectronics technologies, applications, and markets, released a news article on the recent research result by Professor Chang-Hee Nam from the Department of Physics. For the article, please follow the link below:
http://www.laserfocusworld.com/articles/2012/04/kaist-attosecond
2012.04.13 View 8268 -
NPKI Launch Workshop Held
Molecular Physics Department Expected to Have ‘NPKI’ Launch Workshop
- Numerous physicists tracking the god-particle ‘Higgs’ attending-
The NPKI: New Physics at Korea Institute which was launched a six day workshop in Shinla Hotel, Seoul with 50 physicists from in and out of the country.
The event started with Professor Gi Woon Choi’s welcoming speech. A heated debate with the theme ‘Top physics and electroweak symmetry breaking in the LHC era’ took place in the event.
NPKI was created this year to search into the most fundamental workings of nature, research the meaning of such mechanisms, and share this knowledge with not only the general public, but also with the teenagers who wish to someday become physicists.
Professor Gi Woon Choi from KAIST, Professors Byoung Wong Ko and Eung Jin Jeon from the Advanced Science Institute, and more are participated in this workshop from Korea.
From abroad, world renowned professors such as Prof. Csaba Csaki from Cornell, Prof. Christophe Grojean from CERN, Prof. Erez Etzion from Tel Aviv University of Israel, and Prof. Zoltan Ligeti from UC Berkley participated in this event.
The ‘Seeds Program’ took place. This is a program where 20 high school and middle school students aspiring to become physicists were able to attend the work shop without any due fee to experience the world of physicists.
The students chosen for the program were able to attend the conference to watch debates of real physicists as well as experience the academic lives of physicists. They were also able to attend the lecture conducted by Prof. Gilad Perez from CERN and were granted question and answer sessions as well.
The workshop was hosted by NPKI, and sponsored by Shinla Hotel, BK21 KAIST Physics, department of physics of KAIST, department of physics in Seoul National University, the Advanced Science Institute, and the Center for Quantum Spacetime
2012.04.04 View 13785
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New Era for Measuring Ultra Fast Phenomena: Atto Science Era
Domestic researchers successfully measured the exact status of the rapidly changing Helium atom using an atto second pulse. Thanks to this discovery, many ultrafast phenomena in nature can now be precisely measured. This will lead to an opening of a new "Atto Science" era.
Prof. Nam Chang Hee led this research team and Ph.d Kim Kyung Taek and Prof. Choi Nak Ryul also participated in this research. They have conducted the research under the support of the Researcher Support Program initiated by The Ministry of Education and Science and Korea Research Foundation. The research result was published in the prestigious journal "Physical Review Letters" on March 2nd. (Title: Amplitude and Phase Reconstruction of Electron Wave Packets for Probing Ultrafast Photoionization Dynamics)
Prof. Nam Chang Hee"s research team used atto second pulse to measure the ultrafast photoionization.
His team used atto second X-ray pulse and femto second laser pulse to photoionize Helium atoms, and measure the wave speed of the produced electron to closely investigate the ultrafast photoionization process.
Atom"s photoionization measurement using an atto second pulse was possible using the research team"s high-energy femto second laser and high-performance photo ion measurement device. This research team succeeded in producing the shortest 60 atto second pulse in the world using high-harmonic waves.
The research team used high-power femto second laser to produce atto second high-harmonic pulse from argon gas, used this to photoionize Helium atoms, and measured the ultrafast photoionization of the atoms.
Prof. Nam Chang Hee said, "This research precisely measured the exact status of rapidly changing Helium atoms. I am planning to research on measuring the ultrafast phenomena inside atoms and molecules and controlling the status of the atoms and molecules based on the research result."
2012.04.04 View 11319
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New LEDs: Large Spectrum of Colors
Professor Yonghun Cho has discovered that LEDs with hexagonal pyramid structures can emit various colors of light.
LEDs, which have been leading the light revolution is a light emitting element that uses the characteristics of semiconductors to emit light upon passing a current, and is being used for lighting, TV, and various signaling devices.
In general, the white LED used for lighting has to be constructed by spraying yellow fluorescent material on a blue LED or by creating a complicated circuit where various LED chips function together.
Prof.Cho’s research team discovered the fact that when a small hexagonal pyramid structure is formed on the semiconductor composing the LED and a current is passed through this, then each side, edge, and point on the pyramid assumes different energies.
Due to the energy differences, lights of bluegreen, yellow, and orange were emitted from the side, edge, and points of the pyramid, respectively. This shows the prospect of displaying white light as well as that of many other colors.
Thus, applying the nanopyramidal structure to LEDs will allow the emission of light with a large spectrum with just the flow of the current, enabling a new type of LED light emitting particles that would display various colors from a single LED chip without the use of a fluorescent material.
Also, originally, LEDs have had limitations to its efficiency because of its structural characteristics where fluorescent materials had to be sprayed on, but the nanopyramidal structures will overcome this structural barrier to create brighter light
2012.01.31 View 8112
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Dong Ah Newspaper Publish '100 Koreans who will Represent Korea in 10 years'
The 2011 list of ‘100 Koreans who will Represent Korea in 10 years’ published by Dong Ah Newspaper includes people of varying ages, vocation, and gender.
In terms of University Professors, five professors from each of KAIST and SNU (Seoul National University) were selected. Especially Professor Charles Ahn received the most votes due to his world class talent, potential, and dedication.
Professor Kim Sang Wook of the Department of Materials Science and Engineering is the world leading expert in the field of ‘Atom Construction Nanotechnology’ which deals with using macromolecules, carbon nanotubes, and grapheme to form various structures. His work on ‘low cost, large area nano patterning technology’ is expected to overcome the limits of nano treatment processes and its application in semi-conductors or displays carries great promise.
Professor Kim Eun Sung of the Department of Physics discovered a new quantum behavior, supersolidity, in a low temperature, solid Helium for the first time in the world and is the leading scientist that leads the mechanics behind such a phenomenon. Professor Kim is leading the field of supersolidity through his works on hidden phase in a low temperature solid Helium, the understanding the role of crystalline faults in the supersolidity phenomenon, and the destruction of the supersolid’s macromolecular phenomenon through spinning solids.
Professor Charles Ahn of the Graduate School of Innovation and Technology Management has been working as the developer of the V3 series (an anti-computer virus Vaccine Program) since 1988. He established the ‘Charles Ahn Research Center’ in 1995 and his solid and practical management style won him rave reviews. Professor Ahn was appointed as the Professor of the Graduate School of Innovation and Technology Management and has been teaching entrepreneurial perspective and Technology Management.
Professor Lee Sang Yeop of the Department of Biology and Chemical Engineering developed world’s most efficient production method of succinic acid, developed high efficiency, tailored, culture for the production of key amino acids, Valine and Threonine, developed the production culture off bio-buthanol which is superior to bio-ethanol, and is widely known as one of the leaders in the field of metabolic engineering.
Professor Jeong Ha Woong of the Department of Physics is being regarded as world leader in the field of Complex System Network Sciences. He implemented Statistical Physics to Complex Systems and also used the concept of ‘Networks’ and published 80 papers, including 5 which were published in Nature Magazine.
2011.04.30 View 14382
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The 40th Anniversary of the Establishment of KAIST Commemoration Held
KAIST, aspiring to become the best Science and Technology University, has turned 40.
KAIST held the commemoration ceremony for the 40th Anniversary of the Establishment of KAIST in the auditorium.
Five awards (Scholar, Creative Lecture, Excellence in Lecture, International Cooperation, Experiment) were given to Professors Kim Eun Jun and Walton Jones (department of Biology), Professor Abigail Shin (department of Humanities and Social Sciences), Professor Shin Seong Chul (department of Physics), and Professor Lee Sang Yeop (department of Biological Chemical Engineering). Each recipient received a prize of five million won.
Professor Song Joon Hwa (department of Computer Sciences) received the ‘New Knowledge Award’ in recognition of his development of the Orchestrator Mobile platform. The new platform is different from Android or the IOS platform in that it allows a fluid relationship to be formed between the smartphone and the user.
KAIST also showed off its new emblem.
The emblem consists of a star which represents the KAIST’s goals of becoming the world leader, of training leaders, the center point, and hope. The main keywords are: ‘Leadership’, ‘Premium’, ‘Scientific’, and ‘Humanity’.
KAIST plans on having various events from May 9th when there will be the Vision Declaration.
2011.02.21 View 15883
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"Supersolidity flows back," Nature, September 2, 2010
Supersolidity, discovered for the first time in 2004 by two physicists—one of them is Professor Eun-Seong Kim from the Department of Physics, KAIST—was discussed once again in the September 2, 2010 issue of Nature, an internationally well-known science journal.
The article mentioned “supersolidity” as one of the rare examples of quantum effects on a macroscopic scale, together with “superconductivity” and “superfluidity.” The phenomenon of supersolidity was evidenced by Professor Kim and his colleague through an experiment of placing helium-4 in a torsional oscillator under a low temperature.
The phenomenon, however, has been in debate among scientists in the physics community since the discovery, and Professor Kim has recently released his research results to further support his claim. For the full article, please click the link below:
http://www.nature.com/news/2010/100902/full/news.2010.443.html.
2010.09.08 View 10564
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Science News Issued on September 11, 2010: A matter of solidity
Science News, a bi-weekly news magazine of the Society for Science & the Public, published an extensive article on the issue of “supersolidity” discovered in helium-4.
Professor Eun-Seong Kim of the Physics Department, KAIST, is one of the scientists who discovered the phenomenon through an experiment of solid helium using a device called a torsional oscillator.
For the entire article, please click the link of
http://www.sciencenews.org/view/feature/id/62642/title/A_matter_of_solidity.
2010.09.02 View 11480
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The 6th president of KAIST passed away on May 7, 2010.
Dr. Sang-Soo Lee was the first president of Korea Advanced Institute of Science (KAIS) and the 6th president of KAIST, who died of a chronic disease at the age of 85. The KAIS was the matrix of KAIST today. Graduated from the physics department of Seoul National University in 1949, he later received a doctoral degree in optics from Imperial College of Science and Technology, University of London.
Dr. Lee has greatly contributed to the development of science and technology in Korea in the capacity of a policy administrator, educator, scientist, researcher, and engineer. He held numerous prestigious offices including President of Korea Atomic Energy Research Institute in 1967, of KAIS in 172, and of KAIST in 1989. Dr. Lee also worked as a professor at the physics department of KAIST for 20 years from 1972-1992.
The Society of Photographic Instrumentation Engineers (SPIE), an international society for optics and photonics, was founded in 1955 to advance light-based technologies. Dr. Sang-Soo Lee was a member of the SPIE that issued a news release expressing its sincere condolences to his death. The following is the full text of the news release: http://spie.org/x40527.xml
In memoriam: Sang Soo Lee
10 May 2010
Sang Soo Lee, known as the "Father of Optics" in Korea passed away on May 7, 2010, in Korea. He was 84.
Lee received a B.S. in Physics from Seoul National University in Korea and a Ph.D. from Imperial College of Science and Technology, University of London, UK. Receiving the first Ph.D. in Optics in Korea, Dr. Lee devoted his life to lay the foundation for optical science and engineering for more than four decades as an educator, researcher, and administrator in science policy.
"He was one of the architects of the extraordinary and rapid emergence of Korea as a world leader in science and technology, or perhaps with the rich history of contributions centuries ago, re-emergence would be more appropriate." said Eugene G. Arthurs, SPIE Executive Director.
During his teaching career, Dr. Lee mentored 50 doctoral and more than 100 masters" degree candidates. in the areas of laser physics, wave optics, and quantum optics. Many of his former students have become leaders in academia, government-funded research institutes, and industry both in Korea and abroad. He published more than 250 technical papers and authored five textbooks, including "Wave Optics", "Geometrical Optics", "Quantum Optics", and "Laser Speckles and Holography".
Lee was the first president of the Korea Advanced Institute of Science and Technology (KAIST), and the first president to establish a new government funded graduate school. He played a pivotal role in founding the Optical Society of Korea (OSK) in 1989 and served as its first president.
Lee was an active member of the international scientific community. In addition to his pioneering scholastic achievements at KAIST, he served as the Vice President of the International Commission for Optics (ICO), a Council Member of the Third World Academy of Sciences, and a Council Member of UN University, serving as an ambassador for the optics community, which showed a significant example of how a developing country like Korea can serve international optics community.
Dr. Lee was a Fellow of the International Society for Optical Engineering (SPIE), the Optical Society of America (OSA), and the Korean Physical Society (KPS). He was the recipient of many awards and honors, including the National Order of Civil Merit that is the Presidential Medal of Honor from the Republic of Korea (2000), the Songgok Academic Achievement Prize, the Presidential Award for Science, and the Medal of Honor for Distinguished Scientific Achievement in Korea. In 2006, he was awarded OSA"s Esther Hoffman Beller Medal.
2010.05.19 View 15043 -
Professor Eun-Seong Kim and his research staff observed the phenomena of hysteresis and relaxation dynamics from supersolid Helium
Professor Eun-Seong Kim and his research staff observed the phenomena of hysteresis and relaxation dynamics from supersolid Helium.
Their research paper was published in Nature Physics for the issue of April 2010.
If we take Helium 4 and cool it down at temperatures below 2.176 Kelivin, liquid helium 4 undergoes a phase transition and becomes superfluid with a zero viscosity. The superfluidity was observed in solid helium through an experiment performed by researchers of Pennsylvania State University in 2004. One of the researchers then was Professor Eun-Seong Kim in the Department of Physics, KAIST.
Professor Kim and his research staff, Hyung-Soon Choi, Ph.D., recently published their research results in Nature Physics (April 2010), a highly esteemed journal in the field, on the phenomena of hysteresis and relaxation dynamics observed in supersolid Helium.
For the paper, please download the attached .pdf file.
Nature Physics link: http://www.nature.com
2010.04.13 View 13646 -
Scaling Laws between Population and Facility Densities Found
A research team led by Prof. Ha-Woong Jeong of the Department of Physics, KAIST, has found a positive correlation between facilities and population densities, university authorities said on Tuesday (Sept. 2). The research was conducted in the cooperation with a research team of Prof. Beom-Jun Kim at Sungkyunkwan University.
The researchers investigated the ideal relation between the population and the facilities within the framework of an economic mechanism governing microdynamics.
In previous studies based on the global optimization of facility positions in minimizing the overall travel distance between people and facilities, the relation between population and facilities should follow a simple law. The new empirical analysis, however, determined that the law is not a fixed value but spreads in a broad range depending on facility types.
To explain this discrepancy, the researchers proposed a model based on economic mechanism that mimics the competitive balance between the profit of the facilities and the social opportunity cost for population.
The results were published in the Proceedings of the National Academy of Sciences of the United States on Aug. 25.
2009.09.04 View 14317