in Nature: Engineers find better way to detect nanoparticles<p>​It’s long been thought that two’s company and three’s a crowd. But electrical and systems engineers at Washington University in St. Louis and their collaborators have shown that the addition of a third nanoscatterer, complementing two “tuning” nanoscatterers, to a photonics resonator makes for a fascinating physics party.<br/></p><img alt="" src="/news/PublishingImages/Lan%20Yang%20Nature%20Cover%202017.PNG?RenditionID=1" style="BORDER:0px solid;" /><div id="__publishingReusableFragmentIdSection"><a href="/ReusableContent/36_.000">a</a></div><p>Specifically, the two tuning nanoscatterers set the resonator at an "exceptional point," a special state of a system at which unusual phenomena may occur. The third nanoscatterer perturbs the system, and like a nasty playground bully, the smaller it is, the more response it gets.  </p><p>The Washington University team, led by <a href="/Profiles/Pages/Lan-Yang.aspx">Lan Yang, the Edwin H. & Florence G. Skinner Professor of Electrical & Systems Engineering</a>, has made major strides recently in the study and manipulation of light. The team's most recent discovery of the sensing capability of microresonators could have impacts in the creation of biomedical devices, electronics and biohazard detection devices.</p><p>"It's challenging to detect nanoscale objects, such as nanoparticles," Yang said. "If the object is very small, it introduces little perturbation to a sensing system. We utilize an unusual topological feature associated with exceptional points of a physical system to enhance the response of an optical sensor to very small perturbations, such as those introduced by nanoscale objects. The beauty of the exceptional point sensor is the smaller the perturbation, the larger the enhancement compared to a conventional sensor."</p><blockquote>Yang and her collaborators published their results in the Aug. 10, 2017 issue of <em></em><a href="">Nature.</a></blockquote> <p>Yang's sensor system belongs to a category called whispering gallery mode (WGM) resonators, which work like the famous whispering gallery in St. Paul's Cathedral in London, where someone on one side of the dome can hear a message spoken to the wall by someone on the other side. Unlike the dome, which has resonances or sweet spots in the audible range, the sensor resonates at light frequencies.</p><p>"The so-called 'exceptional point' endows a whispering-gallery sensor with exceptional performance for detecting nanoscale objects, surpassing that of conventional whispering-gallery sensors," said Weijian Chen, an electrical engineering doctoral student in Yang's lab. "Strikingly, the smaller the target object is, the better the performance of our new sensor will be."</p><p>Yang's WGM features two companion silica scatterers, or nanotips, which set on the toroid, or donut-shaped wire, the avenue for millions of light packets called photons to traverse. These devices tune various parameters in the system to influence function. Using nanopositioning systems, the researchers can move the scatterers and increase the size and even introduce another medium — a virus particle, for instance — into the field to perturb the field and beckon an exceptional point. </p><p>In the team's most recent experiments, the two "tuning" nanoscatterers bring the resonator to exceptional points; the third particle perturbs the system from its exceptional points and leads to a frequency splitting. Because of the very complex-square-root topology near an exceptional point, the frequency-splitting, which is the sensing signal, is represented mathematically as the square root of the perturbation strength. It is significantly larger than what is found in traditional, non-exceptional point-sensing schemes using very small perturbations.</p><p>Yang and her group are exploring the use of the exceptional point in photoacoustic imaging studies and other scenarios where they seek development of "unconventional light transport modes,' she said. "There should be many applications arising from that."<br/></p> <SPAN ID="__publishingReusableFragment"></SPAN> <p> <br/> </p><p>Chen W, Özdemir S, Zhao G, Wiersig J, Yang L. Exceptional points enhance sensing in an optical microcavity. <em>Nature</em>. Aug. 10, 2017. doi:10.1038/nature23281</p><p>Funding for this research was provided by the National Science Foundation and the Army Research Office. <br/></p>​<br/><br/><br/> <div><div class="cstm-section"><h3>Lan Yang<br/></h3><div style="text-align: center;"> <strong> <a href="/Profiles/Pages/Lan-Yang.aspx"> <img src="/Profiles/PublishingImages/Yang_Lan.jpg?RenditionID=3" alt="Lan Yang" style="margin: 5px;"/></a> <br/> </strong> </div><div style="text-align: center;"> <span style="font-size: 12px;">Professor<br/>Electrical & Systems Engineering<br/><a href="/Profiles/Pages/Lan-Yang.aspx">>> View Bio</a></span></div><div style="text-align: center;"></div></div></div><div><br/> </div> <span> <div class="cstm-section"><h3>Media Coverage<br/></h3><div> <strong>nanowerk: </strong><a href="">Engineers find better way to detect nanoparticles</a><br/></div></div></span><br/> <div> <br/> </div>Two light scatterers, represented by the blue spheres, are utilized to tune the sensors to exceptional points, at which light propagates in one direction. (Image: W. Chen and L. Yang)Tony Fitzpatrick2017-08-09T05:00:00ZElectrical and systems engineers at WashU have shown that the addition of a third nanoscatterer, complementing two “tuning” nanoscatterers, to a photonics resonator makes for a fascinating physics party. awarded U.S. Air Force Office of Scientific Research award<img alt="" src="/Profiles/PublishingImages/Nehorai_Ayre.jpg?RenditionID=1" style="BORDER:0px solid;" /><p>​<a href="/Profiles/Pages/Arye-Nehorai.aspx">Arye Nehorai</a>, the Eugene and Martha Lohman Professor of Electrical Engineering, received a four-year, $740,000 grant from the U.S. Air Force Office of Scientific Research for research titled “Advanced Machine Learning Techniques for Adaptive Radars in Nonstationary Environments.” Nehorai is also director of the Center for Sensor Signal and Information Processing in the School of Engineering & Applied Science.<br/></p>Arye Nehorai2017-08-03T05:00:00ZArye Nehorai is a professor in the Preston M. Green Department of Electrical & Systems Engineering, professor in the Division of Biology and Biomedical Studies (DBBS) and Director of the Center for Sensor Signal and Information Processing at WashU. brain researchers convene at WashU<p>​Some of the nation's leading researchers in brain dynamics and neural engineering came together at WashU to share their research and determine the next steps in the growing field. <br/></p><img alt="" src="/news/PublishingImages/WashU%20engineering%20brain%20workshop%20(1).JPG?RenditionID=1" style="BORDER:0px solid;" /><div id="__publishingReusableFragmentIdSection"><a href="/ReusableContent/News/34_.000">a</a></div><p>The Workshop on Brain Dynamics and Neurocontrol Engineering, headed by <a href="/Profiles/Pages/ShiNung-Ching.aspx">ShiNung Ching</a>, assistant professor, and<a href="/Profiles/Pages/Jr-Shin-Li.aspx"> Jr-Shin Li</a>, associate professor, both in the Department of Electrical & Systems Engineering in the School of Engineering & Applied Science, brought about 90 neuroscientists, engineers and graduate students to the Danforth Campus June 25-27. Themes of the sessions included controlling neural circuits, inferring neural dynamics, and network dynamics and control in neuroscience. It is the first workshop to bring together researchers from systems science and control engineering and the basic sciences of neuroscience, biology and biomedical sciences, Li said. </p><p>The workshop was designed to provide a focused forum to discuss research synergy between experts from the dynamics, control and neuroscience communities. </p><p>"Building on the school's unique systems science & mathematics program, as well as the collaborative culture and institutional strengths, we have continued to push the envelope of systems science and engineering in diverse application domains, including medicine, biology, and biomedical sciences and engineering," Li said. "This workshop embodied our forward-looking approach to systems science, as a discipline not limited to the modeling, construction and design of engineered systems, but a framework upon which to understand the engineering within nature and human society."</p><p>Among the influential speakers were Roger Brockett, a pioneer in the field of systems science and control theory, the An Wang Research Professor of Electrical Engineering & Computer Science at Harvard University, founder of the Harvard Robotics Lab and a member of the U.S. National Academy of Engineering. More than 100 people attended Brockett's presentation at the Cox Distinguished Lecture.<br/></p> <p style="text-align: center;"></p><div style="text-align: center; font-size: 0.9em; color: #444444; font-style: italic;"> <img src="/news/PublishingImages/WashU%20engineering%20brain%20workshop%20(2).JPG?RenditionID=12" class="ms-rtePosition-4" alt="" style="margin: 5px;"/> <br/>Martin Arthur, Jerry Cox, Roger Brockett, ShiNung Ching, Jr-Shin Li<br/></div> <br/> <p></p> <p style="text-align: left;">In addition, influential neuroscientists Steven Schiff, director of the Penn State Center for Neural Engineering at the Huck Institute of the Life Sciences at Penn State University, and John Baillieul, Distinguished Professor of engineering and director of the Boston University Laboratory for Intelligent Mechatronic Systems, were speakers at plenary sessions. </p><p> <a href="/Profiles/Pages/Barani-Raman.aspx">Barani Raman</a>, associate professor of biomedical engineering, also presented to the group on neural dynamics.</p><p>"We hope that the workshop can promote greater awareness of the potential impact of systems engineering as a valuable component within the broader effort to study the brain, and that the presentations and discussions during the workshop may lead to new collaborations," Ching said. </p><p>The workshop also included a poster session featuring the research of 19 graduate students from all over the country who received travel grants to attend the workshop. </p><p>The event was supported with funding from the National Science Foundation, Cox Distinguished Lecture Series, McDonnell Center for Systems Neuroscience, Oak Ridge Association of Universities, Burroughs Wellcome Fund and the School of Engineering & Applied Science. <br/><br/></p> <SPAN ID="__publishingReusableFragment"></SPAN> <p> <br/> </p><p>​<br/></p> <span> <div class="cstm-section"><h3>Workshop on Brain Dynamics & Neurocontrol Engineering 2017<br/></h3><p style="text-align: center;">This workshop aimed to provide a focused forum for the discussion of research synergy between experts from the dynamics, control and neuroscience communities. <br/><br/><a href="">>> Event Website</a><br/></p></div></span>L to R: J. Nathan Kutz, University of Washington; Garrett Stanley, Georgia Tech; Larry Snyder, Washington University in St. Louis; Erik Herzog, Washington University in St. LouisBeth Miller2017-07-03T05:00:00ZSome of the nation's leading researchers in brain dynamics and neural engineering came together at WashU to share their research and determine the next steps in the growing field. faculty join WashU Electrical & Systems Engineering<p>​<a href="/news/Pages/Eleven-new-faculty-to-join-School-of-Engineering-Applied-Science.aspx">Eleven new faculty will join the School of Engineering & Applied Science in the next year</a>, bringing the total number to 94. The Department of Electrical & Systems Engineering will welcome Ulugbek Kamilov, Chuan Wang and Shen Zeng.<br/></p><img alt="" src="/news/PublishingImages/Green%20Hall%20WashU%20engineering.jpg?RenditionID=1" style="BORDER:0px solid;" /><p><strong>Ulugbek Kamilov, assistant professor</strong></p><p></p><ul><li>PhD, electrical engineering<br/></li><li>BSc, MSc, communication systems, École Polytechnique Fédérale de Lausanne, Switzerland<br/></li></ul>Kamilov joins the ESE and CSE departments as a 50/50 appointment from Mitsubishi Electric Research Laboratories in Cambridge, Mass., where he has been a research scientist in computational sensing since 2015. He joins the faculty Sept. 1.<p></p><p style="font-size: medium; color: #000000; font-family: "times new roman";"></p><p>Kamilov’s research areas are developing new techniques for computational imaging in biomedical and industrial applications. His broader research interests include signal and image processing, convex and nonconvex optimization, statistical inference, and machine learning.<br/><br/></p><p><strong>Chuan Wang, assistant professor<br/></strong></p><ul><li>PhD, electrical engineering, University of Southern California<br/></li><li>BS, MS, microelectronics, Peking University, China<br/></li></ul><p>Wang joins ESE from Michigan State University, where he has been an assistant professor of electrical and computer engineering since 2013. Previously, he was a postdoctoral scholar at University of California, Berkeley, and a postdoctoral affiliate at the Lawrence Berkeley National Laboratory. He joins the faculty July 2018.<br/></p><p>Wang’s research interests include flexible and stretchable electronics for display, sensing and energy harvesting applications, as well as low-cost and scalable inkjet printing processes for microfabrication of flexible electronics. In addition, a second main research direction in his group is high-performance nanoelectronics and optoelectronics using two-dimensional semiconductors.<br/><br/></p><p style="font-size: medium; color: #000000; font-family: "times new roman";"></p><p><strong>Shen Zeng, assistant professor</strong></p><p></p><ul><li>PhD, engineering<br/></li><li>MSc, engineering cybernetics<br/></li><li>BSc, mathematics & BSc, mechatronics, University of Stuttgart<br/></li></ul>Zeng joins ESE from the University of Stuttgart, Germany, where he is a postdoctoral researcher and lecturer in the Institute for Systems Theory and Automatic Control. During his time there, he has been heavily involved in both undergraduate and graduate teaching in the broad area of systems and control theory. He joins Aug. 1.<p></p><p style="font-size: medium; color: #000000; font-family: "times new roman";"></p><p>Zeng's research focuses on systems theoretic methods for the study of complex and large-scale dynamical systems. While in the past, systems theoretic insights have proved to be key in better understanding the crucial dynamical nature in related problems on a smaller scale, the recent flood of data in both science and engineering offers novel ways to also get control over the class of complex and large-scale dynamical systems. Zeng in particular seeks to develop computational methods that will efficiently utilize the abundance of available data for both systems analysis and controller synthesis.<br/></p><p>​<br/><br/></p><div><div class="cstm-section" style="font-size: 16px;"><h3>ESE at WashU<br/></h3><div> <strong></strong></div><p style="text-align: center;">Electrical and systems engineers at WashU are dedicated to advancing the frontiers of sensing, imaging, control, security and sustainable energy.<br/></p><p style="text-align: center;"> <a href="">>></a><br/></p></div></div>2017-07-01T05:00:00ZUlugbek Kamilov, Chuan Wang and Shen Zeng join the School of Engineering & Applied Science in 2018. student focuses on ‘healing light’ for health-care patients<p>​As a full-time consultant and electrical engineering student, boredom isn’t a typical state for Marissa Sexton. In fact, she finds herself “just tired all the time.”<br/></p><img alt="" src="/news/PublishingImages/WashU%20UMSL%20Engineering%20Marissa%20Sexton.jpg?RenditionID=1" style="BORDER:0px solid;" /><p> <a href="/our-school/why-wash-u-engineering/partnerships/Pages/umsl-wash-u-joint-undergraduate-engineering-program.aspx"><img src="/news/PublishingImages/UMSL.gif" class="ms-rtePosition-1" alt="" style="margin: 5px 10px; width: 167px;"/></a>On the rare occasion when she had a limited workload during winter break, the senior in the <a href="/our-school/why-wash-u-engineering/partnerships/Pages/umsl-wash-u-joint-undergraduate-engineering-program.aspx" rel="noopener noreferrer">University of Missouri–St. Louis and the Washington University Joint Engineering Program</a> sought out ways to challenge herself and broaden her skill set.</p><p>The self-assigned busywork paid off, as Sexton earned an honorable mention prize from the 40th annual <a href="" target="_blank" rel="noopener noreferrer">SOURCE Awards</a> for her conceptual lighting design of a health-care facility.</p><p>She received the recognition and crystal trophy during a presentation on May 8 at LIGHTFAIR International in Philadelphia. The SOURCE Awards judge conceptual designs that utilize lighting and controls from the product line of Eaton, a power management company.</p><p>Sexton’s submission – “<a href="" target="_blank" rel="noopener noreferrer">Healing Light: Improving lives and bottom lines with LumaWATT Pro</a>” – focused on daylight harvesting to cut costs for the facility and decrease patient stay durations. Energy efficiency and patient and staff satisfaction were prime considerations when utilizing lighting controls and daylight, specifically in the patient rooms, lobby and rehab gym.</p><blockquote>An electrical designer for <a href="" target="_blank" rel="noopener noreferrer">Ross & Baruzzini</a>, Sexton has spent significant time studying the impact of lighting in the domestic health-care market.</blockquote> <p>“Prior to finding the competition, I was researching the way light affects patients because there is all of this new technology coming out,” Sexton said. “We’re in a day in age where we can change color temperatures of fixtures, remotely control lighting and integrate daylighting into our designs. All of this can be incorporated into design for improved patient satisfaction and health. That’s how I came up with the idea for ‘Healing Light.’”</p><p>She hopes implementing towering windows to allow for ambient light will impact patients by increasing protein metabolism, decreasing fatigue, stimulating white blood cells production and decreasing blood pressure. Sexton also accounted for patient access to lighting control, adding a level of comfort and personalization to the space.</p><p>The SOURCE Awards offered six professional and seven student accolades. Judging criteria included the blending of aesthetics, creative achievement, technical performance and the degree to which the lighting met project constraints and design concept goals.</p><p>While many student entries are the capstone project of a semester-long course, Sexton’s design was an independent venture.</p><blockquote>“I was shocked that I had won because I’m not very artistic,” Sexton said. “I was surprised because it was extremely methodical without a lot of flair. They did say the driving factor behind my award was my knowledge of the controls and the codes, which I got experience with as an intern.”</blockquote><p>Graphic representation may have been a struggle initially, but Sexton is now the go-to consultant in her office for the lighting software “Visual.”</p><p>“Dealing with Visual software while I was doing this project definitely gave me a leg up,” Sexton said. “I’ve always been pretty good at it, but I never dove deep down to see what I can actually do.”</p><p>Following her anticipated graduation in December, Sexton plans to continue her work with Ross & Baruzzini. Although her immediate career path is set, the road wasn’t always so clear.</p><p>Originally a mechanical engineering major, Sexton dropped out of the program after realizing it wasn’t her forte. At the time, she contemplated a transfer in schools but stayed after an adviser’s suggestion to try a couple courses in electrical engineering.</p><p>While still unsure where the switch would lead her, Sexton landed an internship at Ross & Baruzzini, which resulted in a full-time offer. The transition also introduced her to a beneficial course taught by Thomas Collins. The adjunct professor of electrical engineering had a way of blending both theory and practical application that resonated with students.</p><p>“We actually looked at spec sheets,” Sexton said. “If I hadn’t had an internship, I never would have seen a spec sheet until Professor Collins’ class. He really tries to tie everything together.”<br/><img src="/news/PublishingImages/WashU%20Engineering%20Student%20Marissa%20Sexton.jpg" class="ms-rtePosition-4" alt="" style="margin: 5px;"/><br/><br/></p>Marissa Sexton was one of seven students honored during the SOURCE Awards presentation in May. She learned of her honorable mention prize during LIGHTFAIR International in Philadelphia. (Photo by August Jennewein)Sara Bell, UMSL Daily electrical designer for Ross & Baruzzini, Marissa Sexton has spent significant time studying the impact of lighting in the domestic health-care market.