Optica
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‘OSK Rising Stars 30’ Recognizes Four KAISTians
Four KAISTians were selected as star researchers to brighten the future of optics in commemoration of the 30th anniversary of the Optical Society of Korea (OSK). As ‘OSK Rising Stars 30’, the OSK named 27 domestic researchers under the age of 40 who have made significant contributions and will continue contributing to the development of Korea’s optics academia and industry.
Professor YongKeun Park from the Department of Physics was selected in recognition of his contributions to the field of biomedical optics. Professor Park focuses on developing novel optical methods for understanding, diagnosing, and treating human diseases, based on light scattering, light manipulation, and interferometry. As a member of numerous international optics societies including the OSA and the SPIE and a co-founder of two start-up companies, Professor Park continues to broaden his boundaries as a leading opticist and entrepreneur.
Professor Jonghwa Shin from the Department of Materials Science and Engineering was recognized for blazing a trail in the field of broadband metamaterials. Professor Shin’s research on the broadband enhancement of the electric permittivity and refractive index of metamaterials has great potential in both academia and industry.
Professor Hongki Yoo from the Department of Mechanical Engineering is expected to create a significant ripple effect in the diagnosis of cardiovascular disorders through the development of new optical imaging techniques and applications.
Finally, Dr. Sejeong Kim, a KAIST graduate and a Chancellor’s postdoctoral research fellow at the University of Technology Sydney (UTS), was acknowledged for her optical device research utilizing two-dimensional materials. Dr. Kim’s research at UTS now focuses on the introduction of micro/nano cavities for new materials.
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2020.03.16 View 5335 -
Two More Cross-generation Collaborative Labs Open
< President Sung-Chul Shin (sixth from the left) and Professor Sun Chang Kim (seventh from the left) at the signboard ceremony of KAIST BioDesigneering Laboratory >
KAIST opened two more cross-generation collaborative labs last month. KAIST BioDesigneering Laboratory headed by Professor Sun Chang Kim from the Department of Biological Sciences and Nanophotonics Laboratory led by Professor Yong-Hee Lee from the Department of Physics have been selected to receive 500 million KRW funding for five years.
A four-member selection committee including the former President of ETH Zürich Professor Emeritus Ralph Eichler and Professor Kwang-Soo Kim of Harvard Medical School conducted a three-month review and evaluation for this selection to be made. With these two new labs onboard, a total of six cross-generation collaborative labs will be operated on campus.
The operation of cross-generation collaborative labs has been in trial since March last year, as one of the KAIST’s Vision 2031 research innovation initiatives. This novel approach is to pair up senior and junior faculty members for sustaining research and academic achievements even after the senior researcher retires, so that the spectrum of knowledge and research competitiveness can be extended to future generations. The selected labs will be funded for five years, and the funding will be extended if necessary. KAIST will continue to select new labs every year.
One of this year’s selectees Professor Sun Chang Kim will be teamed up with Professor Byung-Kwan Cho from the same department and Professor Jung Kyoon Choi from the Department of Bio and Brain Engineering to collaborate in the fields of synthetic biology, systems biology, and genetic engineering. This group mainly aims at designing and synthesizing optimal genomes that can efficiently manufacture protein drug and biomedical active materials. They will also strive to secure large amounts of high-functioning natural active substances, new adhesive antibacterial peptides, and eco-friendly ecological restoration materials. It is expected that collaboration between these three multigenerational professors will help innovate their bio-convergence technology and further strengthen their international competitiveness in the global bio-market.
Another world-renowned scholar Professor Yong-Hee Lee of photonic crystal laser study will be joined by Professor Minkyo Seo from the same department and Professor Hansuek Lee from the Graduate School of Nanoscience and Technology. They will explore the extreme limits of light-material interaction based on optical micro/nano resonators, with the goal of developing future nonlinear optoelectronic and quantum optical devices. The knowledge and technology newly gained from the research are expected to provide an important platform for a diverse range of fields from quantum communications to biophysics.
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2019.09.06 View 4319 -
KAIST Develops Core Technology for Ultra-small 3D Image Sensor
(from left: Dr. Jong-Bum Yo, PhD candidate Seong-Hwan Kimand Professor Hyo-Hoon Park)
A KAIST research team developed a silicon optical phased array (OPA) chip, which can be a core component for three-dimensional image sensors. This research was co-led by PhD candidate Seong-Hwan Kim and Dr. Jong-Bum You from the National Nanofab Center (NNFC).
A 3D image sensor adds distance information to a two-dimensional image, such as a photo, to recognize it as a 3D image. It plays a vital role in various electronics including autonomous vehicles, drones, robots, and facial recognition systems, which require accurate measurement of the distance from objects.
Many automobile and drone companies are focusing on developing 3D image sensor systems, based on mechanical light detection and ranging (LiDAR) systems. However, it can only get as small as the size of a fist and has a high possibility of malfunctioning because it employs a mechanical method for laser beam-steering.
OPAs have gained a great attention as a key component to implement solid-state LiDAR because it can control the light direction electronically without moving parts. Silicon-based OPAs are small, durable, and can be mass-produced through conventional Si-CMOS processes.
However, in the development of OPAs, a big issue has been raised about how to achieve wide beam-steering in transversal and longitudinal directions. In the transversal direction, a wide beam-steering has been implemented, relatively easily, through a thermo-optic or electro-optic control of the phase shifters integrated with a 1D array. But the longitudinal beam-steering has been remaining as a technical challenge since only a narrow steering was possible with the same 1D array by changing the wavelengths of light, which is hard to implement in semiconductor processes.
If a light wavelength is changed, characteristics of element devices consisting the OPA can vary, which makes it difficult to control the light direction with reliability as well as to integrate a wavelength-tunable laser on a silicon-based chip. Therefore, it is essential to devise a new structure that can easily adjust the radiated light in both transversal and longitudinal directions.
By integrating tunable radiator, instead of tunable laser in a conventional OPA, Professor Hyo-Hoon Park from the School of Electrical Engineering and his team developed an ultra-small, low-power OPA chip that facilitates a wide 2D beam-steering with a monochromatic light source.
This OPA structure allows the minimizing of the 3D image sensors, as small as a dragonfly’s eye.
According to the team, the OPA can function as a 3D image sensor and also as a wireless transmitter sending the image data to a desired direction, enabling high-quality image data to be freely communicated between electronic devices.
Kim said, “It’s not an easy task to integrate a tunable light source in the OPA structures of previous works. We hope our research proposing a tunable radiator makes a big step towards commercializing OPAs.”
Dr. You added, “We will be able to support application researches of 3D image sensors, especially for facial recognition with smartphones and augmented reality services. We will try to prepare a processing platform in NNFC that provides core technologies of the 3D image sensor fabrication.”
This research was published in Optics Letters on January 15.
Figure 1.The manufactured OPA chip
Figure 2. Schematic feature showing an application of the OPA to a 3D image sensor
2019.02.08 View 3771 -
Professor Jungwon Kim Wins Haerim Optics and Photonics Award
(Professor Jungwon Kim)
Professor Jungwon Kim from the Department of Mechanical Engineering received the 8th Haerim Optics and Photonics Award from the Optical Society of Korea (OSK).
He was recognized for his dedication to pioneering the field of microwave photonics by developing ultra-low noise fiber photonics lasers.
The Haerim Optics and Photonics Award is given to an outstanding researcher who has made academic contributions in the field of optics and photonics for the last five years.
The name of the award (Haerim) comes from the pen-name of the renowned scholar, Professor Un-Chul Paek, because it is maintained using funds he contributed to the OSK.
The OSK will confer the award on February 8 during the 29th OSK Annual Meeting and Winter Conference of 2018.
2018.02.07 View 3776 -
Meet the KAISTian of 2017, Professor YongKeun Park
Professor YongKeun Park from the Department of Physics is one of the star professors in KAIST. Rising to the academic stardom, Professor Park’s daily schedule is filled with series of business meetings in addition to lab meetings and lectures.
The year 2017 must have been special for him. During the year, he published numerous papers in international journals, such as Nature Photonics, Nature Communications and Science Advances. These high performances drew international attention from renowned media, including Newsweek and Forbes. Moreover, recognizing his research performance, he was elected as a fellow member of the Optical Society (OSA) in his mid-30s. Noting that the members’ age ranges from late 50s to early 60s, Professor Park’s case considered to be quite exceptional.
Adding to his academic achievement, he has launched two startups powered of his own technologies. One is called Tomocube, a company specialized in 3-D imaging microscope using holotomography technology. His company is currently exporting the products to multiple countries, including the United States and Japan. The other one is The.Wave.Talk which has technologies for examining pre-existing bacteria anywhere and anytime.
His research career and entrepreneurship are well deserved recipient of many honors. At the 2018 kick-off ceremony, Professor Park was awarded the KAISTian of 2017 in recognition of his developing holographic measure and control technology as well as founding a new field for technology application.
KAISTian of the Year, first presented in 2001, is an award to recognize the achievements and exemplary contribution of KAIST member who has put significant effort nationally and internationally, enhancing the value of KAIST.
While receiving the award, he thanked his colleagues and his students who have achieved this far together. He said, “I would like to thank KAIST for providing environment for young professors like me so that we can engage themselves in research. Also, I would like to mention that I am an idea seeder and my students do the most of the research. So, I appreciate my students for their hard works, and it is very pleasure to have them. Lastly, I thank the professors for teaching these outstanding students. I feel great responsibility over this title. I will dedicate myself to make further progress in commercializing technology in KAIST.”
Expecting his successful startup cases as a model and great inspiration to students as well as professors, KAIST interviewed Professor Park.
Q What made you decide to found your startups?
A I believed that my research areas could be further used. As a professor, I believe that it is a university’s role to create added value through commercializing technology and creating startups.
Q You have co-founded two startups. What is your role in each company?
A So, basically I have two full-time jobs, professor in KAIST and CTO in Tomocube. After transferring the technology, I hold the position of advisor in The.Wave.Talk.
(Holographic images captured by the product Professor Park developed)
Q Do your students also participate in your companies or can they?
A No, the school and companies are separate spaces; in other words, they are not participating in my companies. They have trained my employees when transferring the technologies, but they are not directly working for the companies.
However, they can participate if they want to. If there’s a need to develop a certain technology, an industry-academia contract can be made. According to the agreement, students can work for the companies.
Q Were there any hardships when preparing the startups?
A At the initial stage, I did not have a financial problem, thanks to support from Startup KAIST. Yet, inviting capital is the beginning, and I think every step I made to operate, generate revenue, and so on is not easy.
Q Do you believe KAIST is startup-friendly?
A Yes, there’s no school like KAIST in Korea and any other country. Besides various programs to support startup activities, Startup KAIST has many professors equipped with a great deal of experience. Therefore, I believe that KAIST provides an excellent environment for both students and professors to create startups.
Q Do you have any suggestion to KAIST institutionally?
A Well, I would like to make a comment to students and professors in KAIST. I strongly recommend them to challenge themselves by launching startups if they have good ideas. Many students wish to begin their jobs in government-funded research institutes or major corporates, but I believe that engaging in a startup company will also give them valuable and very productive experience.
Unlike before, startup institutions are well established, so attracting good capital is not so hard. There are various activities offered by Startup KAIST, so it’s worthwhile giving it a try.
Q What is your goal for 2018 as a professor and entrepreneur?
A I don’t have a grand plan, but I will work harder to produce good students with new topics in KAIST while adding power to my companies to grow bigger.
By Se Yi Kim from the PR Office
2018.01.03 View 6188 -
Professor YongKeun Park Elected as a Fellow of the Optical Society
Professor YongKeun Park, from the Department of Physics at KAIST, was elected as a fellow member of the Optical Society (OSA) in Washington, D.C. on September 12. Fellow membership is given to members who have made a significant contribution to the advancement of optics and photonics.
Professor Park was recognized for his research on digital holography and wavefront control technology.
Professor Park has been producing outstanding research outcomes in the field of holographic technology and light scattering control since joining KAIST in 2010. In particular, he developed and commercialized technology for a holographic telescope. He applied it to various medical and biological research projects, leading the field worldwide.
In the past, cells needed to be dyed with fluorescent materials to capture a 3-D image. However, Professor Park’s holotomography (HT) technology can capture 3-D images of living cells and tissues in real time without color dyeing. This technology allows diversified research in the biological and medical field.
Professor Park established a company, Tomocube, Inc. in 2015 to commercialize the technology. In 2016, he received funding from SoftBank Ventures and Hanmi Pharmaceutical. Currently, major institutes, including MIT, the University of Pittsburgh, the German Cancer Research Center, and Seoul National University Hospital are using his equipment.
Recently, Professor Park and his team developed technology based on light scattering measurements. With this technology, they established a company called The Wave Talk and received funding from various organizations, such as NAVER. Its first product is about to be released.
Professor Park said, “I am glad to become a fellow member based on the research outcomes I produced since I was appointed as a professor at KAIST. I would like to thank the excellent researchers as well as the school for its support. I will devote myself to continuously producing novel outcomes in both basic and applied fields.”
Professor Park has published nearly 100 papers in renowned journals including Nature Photonics, Nature Communications, Science Advances, and Physical Review Letters.
2017.10.18 View 6327 -
Next-Generation Holographic Microscope for 3D Live Cell Imaging
KAIST researchers have developed a revolutionary bio-medical imaging tool, the HT-1, to view and analyze cells, which is commercially available.
Professor YongKeun Park of the Physics Department at KAIST and his research team have developed a powerful method for 3D imaging of live cells without staining. The researchers announced the launch of their new microscopic tool, the holotomography (HT)-1, to the global marketplace through a Korean start-up that Professor Park co-founded, TomoCube (www.tomocube.com).
Professor Park is a leading researcher in the field of biophotonics and has dedicated much of his research career to working on digital holographic microscopy technology. He collaborated with TomoCube’s R&D team to develop a state-of-the-art, 2D/3D/4D holographic microscope that would allow a real-time label-free visualization of biological cells and tissues.
The HT is an optical analogy of X-ray computed tomography (CT). Both X-ray CT and HT share the same physical principle—the inverse of wave scattering. The difference is that HT uses laser illumination whereas X-ray CT uses X-ray beams. From the measurement of multiple 2D holograms of a cell, coupled with various angles of laser illuminations, the 3D refractive index (RI) distribution of the cell can be reconstructed. The reconstructed 3D RI map provides structural and chemical information of the cell including mass, morphology, protein concentration, and dynamics of the cellular membrane.
The HT enables users to quantitatively and non-invasively investigate the intrinsic properties of biological cells, for example, dry mass and protein concentration. Some of the research team’s breakthroughs that have leveraged HT’s unique and special capabilities can be found in several recent publications, including a lead article on the simultaneous 3D visualization and position tracking of optically trapped particles which was published in Optica on April 20, 2015.
Current fluorescence confocal microscopy techniques require the use of exogenous labeling agents to render high-contrast molecular information. Therefore, drawbacks include possible photo-bleaching, photo-toxicity, and interference with normal molecular activities. Immune or stem cells that need to be reinjected into the body are considered particularly difficult to employ with fluorescence microscopy.
“As one of the two currently available, high-resolution tomographic microscopes in the world, I believe that the HT-1 is the best in class regarding specifications and functionality. Users can see 3D/4D live images of cells, without fixing, coating or staining cells. Sample preparation times are reduced from a few days or hours to just a few minutes,” said Professor Park.
Two Korean hospitals, Seoul National University Hospital in Bundang and Boramae Hospital in Seoul, are using this microscope currently. The research team has also introduced the HT-1 at the Photonics West Exhibition 2016 that took place on February 16-18 in San Francisco, USA.
Professor Park added, “Our technology has set a new paradigm for cell observation under a microscope. I expect that this tomographic microscopy will be more widely used in future in various areas of pharmaceuticals, neuroscience, immunology, hematology, and cell biology.”
Figure 1: HT-1 and Its Specifications
Figure 2: 3D Images of Representative Biological Cells Taken with the HT-1
2016.03.29 View 9537 -
Professors Jeon and Choi Receive the Young Scientist Award
Professors Seokwoo Jeon of the Department of Materials Science and Engineering and Jang Wook Choi of the Graduate School of Energy, Environment, Water and Sustainability (EEWS) at KAIST received the Young Scientist Award.
The award ceremony took place at the Korea Press Center in Seoul. Presented by the Ministry of Science, ICT and Future Planning of Korea and the National Academy of Engineering of Korea, the Young Scientist Award is given to outstanding scientists under the age of 40 who have demonstrated excellence in their research in the field of natural science.
Each year the award is given to three scientists in different areas.
Professor Jeon was recognized for his achievement in creating a new property of materials. He studied synthesis and development of low-dimensional nanomaterials and developed a large area nanostructure.
Professor Choi’s research area was to discover optimal materials for rechargeable batteries. By applying his research, he developed rechargeable batteries with high efficiency, making the wearable system more feasible.
2016.01.11 View 6267 -
Professor Woontack Woo Demonstrates an Optical Platform Technology for Augmented Reality at Smart Cloud Show
Professor Woontack Woo of the Graduate School of Culture Technology at KAIST participated in the Smart Cloud Show, a technology exhibition, hosted by the university’s Augmented Human Research Center and presented the latest development of his research, an optical platform system for augmented reality.
This event took place on September 16-17, 2015 at Grand Seoul Nine Tree Convention Center in Seoul.
At the event, Professor Woo introduced a smart glass with an embedded augmented reality system, which permits remote collaboration between an avatar and the user’s hand.
The previous remote collaboration was difficult for ordinary users to employ because of its two-dimensional screen and complicated virtual reality system.
However, with the new technology, the camera attached to artificial reality (AR) glasses recognizes the user’s hand and tracks it down to collaborate. The avatar in the virtual space and the user’s hand interact in real space and time.
The key to this technology is the stable, real-time hand-tracking technique that allows the detection of the hand’s locations and the recognition of finger movements even in situations of self-occlusion.
Through this method, a user can touch and manipulate augmented contents as if they were real-life objects, thereby collaborating remotely with another user who is physically distant by linking his or her movements with an avatar.
If this technology is adopted widely, it may bring some economic benefits such as increased productivity due to lower costs for mobility and reduction in social overhead costs from the decrease in the need of traveling long distance.
Professor Woo said, “This technology will provide us with a greater opportunity for collaboration, not necessarily restricted to physical travelling, which can be widely used in the fields of medicine, education, entertainment, and tourism.”
Professor Woo plans to present his research results on hand-movement tracking and detection at the 12th International Conference on Ubiquitous Robots and Ambient Intelligence (URAI 2015), to be held on October 28-30, 2015, at Kintex in Goyang, Korea.
He will also present a research paper on remote collaboration at the ICAT-EGVE 2015 conference, the merger of the 25th International Conference on Artificial Reality and Telexistence (ICAT 2015) and the 20th Eurographics Symposium on Virtual Environments (EGVE 2015), which will take place on October 28-30, 2015 at the Kyoto International Community House, Kyoto, Japan.
2015.09.16 View 4567 -
Dr. Se-Jung Kim Receives the Grand Prize at the International Photo and Image Contest on Light
Dr. Se-Jung Kim of the Physics Department at KAIST received the Grand Prize at the 2015 Photo and Image Contest of the International Year of Light and Light-based Technologies.
The United Nations has designated the year 2015 as the International Year of Light and Light-based Technologies.
The Optical Society of Korea celebrated the UN’s designation by hosting an international photo and image contest on the theme of light and optics related technology.
Dr. Kim presented a photo of images taken from a liquid crystal, which was entitled “A Micro Pinwheel.” She took pictures of liquid crystal images with a polarizing microscope and then colored the pictures. The liquid crystal has self-assembled circle domain structures, and each domain can form vortex optics. Her adviser for the project is Professor Yong-Hoon Cho of the Physics Department.
Her work was exhibited during the annual conference of the Optical Society of Korea, which was held on July 13-15, 2015 at Gyeong-Ju Hwabaek International Convention Center. It will also be exhibited at the National Science Museum in Gwacheon and the Kim Dae-Jung Convention Center in Gwangju.
Picture: A Micro Pinwheel
2015.07.31 View 5538 -
Professor Kyoungsik Yu Receives the Young IT Engineer Award from IEEE and IEIE of Korea
Professor Kyoungsik Yu of KAIST’s Department of Electrical Engineering is the recipient of this year’s Young IT (Information Technology) Engineer Award that was co-hosted by the Institute of Electrical and Electronics Engineers (IEEE), the Institute of Electronics Engineers of Korea (IEIE), and Haedong Science Culture Foundation in Korea. The award was presented on June 22, 2015 at The Ramada Plaza Jeju Hotel on Jeju Island, Korea.
The Young IT Engineer Award is given to emerging scientists who have made significant contributions to the advancement of technology, society, environment, and creative education.
Professor Yu's main research interests are IT, energy, and imaging through miniaturization and integration of optoelectronic devices. His contribution to academic and technological development is reflected in his publication of more than 100 papers in international journals and conferences, which were cited over 2,200 times.
Professor Yu said, “I’m honored to receive this award and am encouraged by it. I also find the award meaningful because the United Nations has designated this year as the “International Year of Light and Light-based Technologies,” the field I have been involved in as a researcher.”
In addition to Korea, the IEEE has jointly hosted and presented this award to researchers in countries such as Chile, Ecuador, Peru, Singapore, and Italy.
2015.06.22 View 6157 -
Fast, Accurate 3D Imaging to Track Optically-Trapped Particles
KAIST researchers published an article on the development of a novel technique to precisely track the 3-D positions of optically-trapped particles having complicated geometry in high speed in the April 2015 issue of Optica.
Optical tweezers have been used as an invaluable tool for exerting micro-scale force on microscopic particles and manipulating three-dimensional (3-D) positions of particles. Optical tweezers employ a tightly-focused laser whose beam diameter is smaller than one micrometer (1/100 of hair thickness), which generates attractive force on neighboring microscopic particles moving toward the beam focus. Controlling the positions of the beam focus enabled researchers to hold the particles and move them freely to other locations so they coined the name “optical tweezers.”
To locate the optically-trapped particles by a laser beam, optical microscopes have usually been employed. Optical microscopes measure light signals scattered by the optically-trapped microscopic particles and the positions of the particles in two dimensions. However, it was difficult to quantify the particles’ precise positions along the optic axis, the direction of the beam, from a single image, which is analogous to the difficulty of determining the front and rear positions of objects when closing an eye due to a lack of depth perception. Furthermore, it became more difficult to measure precisely 3-D positions of particles when scattered light signals were distorted by optically-trapped particles having complicated shapes or other particles occlude the target object along the optic axis.
Professor YongKeun Park and his research team in the Department of Physics at the Korea Advanced Institute of Science and Technology (KAIST) employed an optical diffraction tomography (ODT) technique to measure 3-D positions of optically-trapped particles in high speed. The principle of ODT is similar to X-ray CT imaging commonly used in hospitals for visualizing the internal organs of patients. Like X-ray CT imaging, which takes several images from various illumination angles, ODT measures 3-D images of optically-trapped particles by illuminating them with a laser beam in various incidence angles.
The KAIST team used optical tweezers to trap a glass bead with a diameter of 2 micrometers, and moved the bead toward a white blood cell having complicated internal structures. The team measured the 3-D dynamics of the white blood cell as it responded to an approaching glass bead via ODT in the high acquisition rate of 60 images per second. Since the white blood cell screens the glass bead along an optic axis, a conventionally-used optical microscope could not determine the 3-D positions of the glass bead. In contrast, the present method employing ODT localized the 3-D positions of the bead precisely as well as measured the composition of the internal materials of the bead and the white blood cell simultaneously.
Professor Park said, “Our technique has the advantage of measuring the 3-D positions and internal structures of optically-trapped particles in high speed without labelling exogenous fluorescent agents and can be applied in various fields including physics, optics, nanotechnology, and medical science.”
Kyoohyun Kim, the lead author of this paper (“Simultaneous 3D Visualization and Position Tracking of Optically Trapped Particles Using Optical Diffraction Tomography”), added, “This ODT technique can also apply to cellular-level surgeries where optical tweezers are used to manipulate intracellular organelles and to display in real time and in 3-D the images of the reaction of the cell membrane and nucleus during the operation or monitoring the recovery process of the cells from the surgery.”
The research results were published as the cover article in the April 2014 issue of Optica, the newest journal launched last year by the Optical Society of America (OSA) for rapid dissemination of high-impact results related to optics.
Figure 1: This picture shows the concept image of tweezing an optically-trapped glass bead on the cellular membrane of a white blood cell.
Figure 2: High-speed 3-D images produced from optical diffraction tomography technique
2015.04.24 View 9467