ECE Professor Yon Visell and UCSB researchers develop a fast, low-voltage actuator for soft and wearable robotics

May 23rd, 2018

image from the cover of AFM
Visell, chemistry & biochemistry professor Thuc-Quyen Nguyen and postdocs Thanh Nho Do and Hung Phan author paper that appears on the cover of the journal Advanced Functional Materials

In the world of robotics, soft robots are the new kids on the block. The unique capabilities of these automata are to bend, deform, stretch, twist or squeeze in all the ways that conventional rigid robots cannot.

Today, it is easy to envision a world in which humans and robots collaborate — in close proximity — in many realms. Emerging soft robots may help to ensure that this can be done safely, and in a way that syncs to human environments or even interfaces with humans themselves.

“Some of the advantages of soft robotic systems are that they can easily adapt to unstructured environments, or to irregular or soft surfaces, such as the human body,” said UC Santa Barbara electrical and computer engineering professor Yon Visell.

Despite their promise, to date, most soft robots move slowly and clumsily when compared with many conventional robots. However, the gap is narrowing thanks to new developments in the fundamental unit of robotic motion: the actuator. Responsible for the mechanical movement of a mechanism or a machine, actuators do their work in various ways, relying on electromagnetic, piezoelectric, pneumatic or other forces.

Now, Visell and his UCSB collaborators have married the electromagnetic drives used in most conventional robotic systems with soft materials, in order to achieve both speed and softness. “An interesting biological analog to the actuator described in our new work might be a fast twitch muscle,” said Visell who along with Professor Thuc-Quyen Nguyen and the postdocs, authored the paper “Soft Electromagnetic Actuators for Robotic Applications.”

The main challenge for Visell and colleagues was to build an actuator that could achieve speeds greater than what has typically been possible with soft robotic actuators, many of which depend on slow processes, such as air flow or thermal effects.

“In this project, we wanted to see how far we could push the idea of having very fast, low-voltage actuation within a fully soft robotic paradigm,” he said. They based their work on the electromagnetic motor, a common type of fast and low-voltage actuator that is used in everything from electric cars to appliances, but has seen little effective application in soft robotic systems.

The team’s work has resulted in a type of actuator that is fast, low voltage and soft — and also remarkably small, just a few millimeters in size. Using unique, liquid-metal alloy conductors encased in hollow polymer fibers and magnetized polymer composites, the researchers created patterned, three-dimensional components that form the basis of soft analogs of standard electrical motors. The fibers themselves are polymer composites that the team engineered to have high thermal conductivity, greatly improving their performance.

The UCSB Current – "Soft Machines" (full article)

Visell's COE Profile

Visell's RE Touch Lab

ECE Ph.D. alum Jiahao Kang receives the 2018 UCSB Winifred and Louis Lancaster Dissertation Award for Mathematics, Physical Sciences & Engineering

May 22nd, 2018

photo of jiahao kang
As the Lancaster recipient, Kang is the only College of Engineering graduate student awardee invited to be a member of the Graduate Division Commencement Ceremony’s Platform Party

In his dissertation titled, “Two-Dimensional Electronic Materials and Devices – Opportunities and Challenges,” Kang focuses on understanding the fundamental issues in 2D materials, such as contacts, interfaces and doping, and in identifying device applications uniquely enabled by these materials. His contributions to the physics of metal contacts to 2D semiconductors, dielectric interfaces and doping have transformed 2D semiconductors from solely scientifically-interesting materials into high-performance electronic devices and also paved the way for a number of radical innovations for his research lab. This includes a novel graphene-based on-chip inductor technology exploiting the kinetic inductance with both small form-factors and high-inductance density, that were once thought unachievable in tandem.

According to Graduate Division Dean Carol Genetti, the Lancaster Award Committee selected Kang’s dissertation due to its sophistication, originality, and exceptional scholarship. His dissertation will serve as UCSB’s Mathematics, Physical Sciences and Engineering entrant in the Council of Graduate Schools (CGS)/ProQuest Distinguished Dissertation Award competition. The Winifred and Louis Lancaster Dissertation Awards are named after two community leaders who contributed time, talent, and financial resources to UCSB for more than half a century.

Kang was a member of ECE Professor Kaustav Banerjee’s Nanoelectronics Research Lab (NRL) and is the second member in a row from NRL to receive the Lancaster Award. Upon graduation, he joined Royole Corporation, a Silicon Valley startup developing flexible electronics. During his doctoral research, he contributed to around 50 papers including five Nature, 11 IEDM, Nano Letters, ACS Nano, Physical Review X, IEEE Electron Device Letters, IEEE Transactions on Electron Devices, and Applied Physics Letters. According to Google Scholar, Kang’s total number of citations exceeds 2100 with an h-index of 17. In 2016 Kang was awarded the Peter J. Frenkel Foundation Fellowship from UCSB’s Institute for Energy Efficiency and the IEEE Electron Devices Society PhD Fellowship. His research interests are at the intersection of nanotechnology, materials physics and electronics.

Dr. Kang will be recognized at the 2018 Graduate Division Commencement Ceremony held on Sunday, June 17 on the UCSB Commencement Green.

UCSB Winifred and Louis Lancaster Dissertation Awards

Kang’s Google Scholar Page

Nanoelectronics Research Lab

ECE Professor Kaustav Banerjee’s research article among the Top 100 read materials science papers for Scientific Reports in 2017

May 8th, 2018

scientific reports top 100 badge Research from Banerjee’s lab demonstrating the first two-dimensional (2D) quantum dot superlattice included as a Top 100 highly accessed article published by the Nature group journal

The research article “Designing artificial 2D crystals with site and size controlled quantum dots” is co-authored by ECE Ph.D. candidate Xuejun Xie, recent ECE Ph.D. alum Jiahao Kang, post-doctoral scholars Wei Cao and Jae Hwan Chu, as well as collaborators from Rice University.

In early Fall 2017, Banerjee’s lab made waves by developing a technique to fabricate large-scale quantum dot superlattices in which each quantum dot’s size and location could be precisely controlled on an atomically thin sheet of two-dimensional (2D) layered semiconductor molybdenum disulphide (MoS2). The technique allowed the quantum dots to be placed close enough to interact with one other, thereby forming an artificial crystal — essentially a new 2D semiconductor material where the band gap can be specified to order, a radical technology that could usher a new generation of light-emitting devices for photonics applications.

According to the congratulatory note received from the journal’s Chief Editor, a position in the top 100 most highly read articles is an extraordinary achievement, since the journal published more than 4500 materials science papers in 2017.

Scientific Reports – "Top 100 in Materials Science"

Banerjee's Nanoelectronics Research Lab

Banerjee's 2D Superlattice in News Media

ECE Professors John Bowers & Luke Theogarajan and UCSB graduate student researchers (GSRs) work together in “Shrinking the Synthesizer”

May 4th, 2018

illustration of a comb generators
Bowers, Theogarajan and four UCSB GSRs produce significant advances in chip-based integrated photonics and nonlinear optics that enable miniature, energy-efficient components for an optical synthesizer – with their findings appearing in the journal Nature

Only a few decades ago, finding a particular channel on the radio or television meant dialing a knob by hand and then making small adjustments to home in on the right signal. That’s no longer the case, thanks to something called a radio-frequency synthesizer, which generates accurate signal frequencies.

While radio frequency control has long since been mastered, optical frequency control still exists in the bygone “tuner knob” era. This is because optical frequencies are so much higher (200 million megahertz) than radio frequencies (100 megahertz). Setting the absolute frequency, or color, of light emitted from a laser with precision is difficult because laser frequencies tend to drift as radio stations once did.

Optical frequency synthesizers provide unprecedented performance but until now have been large, expensive and power hungry. To address these limitations, the Defense Advanced Research Projects Agency (DARPA) in 2014 launched the Direct On-Chip Digital Optical Synthesizer (DODOS) program.

“We took something that occupied a whole optical bench, weighed 50 pounds and used a kilowatt of power and made it orders of magnitude more efficient by integrating the key elements onto silicon photonic integrated circuits,” said Bowers, UCSB’s Fred Kavli Chair in Nanotechnology and director of the campus’s Institute for Energy Efficiency.

The UCSB Current – “Shrinking the Synthesizer” (full article)

Nature (557, pp. 81–85, 2018) – "An optical-frequency synthesizer using integrated photonics"

Bowers' COE Profile

Theogarajan's COE Profile

ECE Prof. Dmitri Strukov and team’s research on integrated memristors and cybersecurity applications featured on the cover of Nature Electronics

April 25th, 2018

illustration of a memristor as a cybersecurity device

UCSB reseachers use emerging memory devices to develop electronic circuits for cybersecurity applications

While we embrace the way the Internet of Things already is making our lives more streamlined and convenient, the cybersecurity risk posed by millions of wirelessly connected gadgets, devices and appliances remains a huge concern. Even single, targeted attacks can result in major damage; when cybercriminals control and manipulate several nodes in a network, the potential for destruction increases.

UC Santa Barbara computer science professor Dmitri Strukov is working to address the latter. He and his team are looking to put an extra layer of security on the growing number of internet- and Bluetooth-enabled devices with technology that aims to prevent cloning, the practice by which nodes in a network are replicated and then used to launch attacks from within the network. A chip that deploys ionic memristor technology, it is an analog memory hardware solution to a digital problem.

“You can think of it as a black box,” said Strukov, whose new paper, “Hardware-intrinsic security primitives enabled by analogue state and nonlinear conductance variations in integrated memristors,” appears on the cover of Nature Electronics. Due to its nature, the chip is physically unclonable and can thus render the device invulnerable to hijacking, counterfeiting or replication by cyber criminals.

Key to this technology is the memristor, or memory resistor — an electrical resistance switch that can “remember” its state of resistance based on its history of applied voltage and current. Not only can memristors can change their outputs in response to their histories, but each memristor, due to the physical structure of its material, also is unique in its response to applied voltage and current. Therefore, a circuit made of memristors results in a black box of sorts, as Strukov called it, with outputs extremely difficult to predict based on the inputs.

“The idea is that it’s hard to predict, and because it’s hard to predict, it’s hard to reproduce,” Strukov said. The multitude of possible inputs can result in at least as many outputs — the more memristors, the more possibilities. Running each would take more time than an attacker may reasonably have to clone one device, let alone a network of them.

The UCSB Current – "The Ionic Black Box" (full article)

Nature Electronics (vol. 1 issue 3, March 2018) – "Memristor Circuits are Tuned for Security"

Strukov's COE Profile

ECE Professor Umesh Mishra selected by the Faculty Senate as the 2017-2018 UCSB Faculty Research Lecturer

April 18th, 2018

mishra sitting on the stairs of ESB
Mishra to deliver the lecture titled “Saving Power is Cool; Really” in the fall quarter of 2018

As we hurtle into a future dominated by the Internet of Things, in which countless devices streamline our lives while producing a prodigious amount of data every second, one thing is clear: Our growing number of machines, gadgets and appliances will need to become far more energy-efficient not just to perform their functions, but also to manipulate that deluge of data.

In addition, our power grids will need to become smarter to respond to the variable needs of the expanding population even as the world works to reduce its reliance on greenhouse gas-producing fossil fuels. Whereas speed — faster computers, high-speed data to your phone — continues to drive innovation, higher energy efficiency or reduced waste is now equally, if not more, important.

Fortunately, the world’s increasing energy needs have been anticipated by forward-looking thinkers, among them Umesh Mishra, UC Santa Barbara professor of electrical and computer engineering. Regarded by his peers in academia and in industry as a world expert in wide-bandgap materials, particularly gallium nitride (GaN), Mishra took what was a promising yet notoriously difficult material to work with and turned it into a cornerstone of energy-efficient power electronics, from efficient microwave power transmitters to energy conversion.

In recognition of his considerable contributions in the research and development of energy-efficient microwave and energy conversion power electronics, which have resulted in a market valued in the hundreds of millions of dollars as well as added to a thriving green industry, Mishra has been selected as UCSB’s 2018 Faculty Research Lecturer. It is the highest honor bestowed upon UCSB professors by their peers and recognizes extraordinary scholarly distinction.

“The understanding of the Earth’s limited resources and human impact on the planet is changing the world, where the efficiency of electronic devices is being valued alongside performance,” Mishra said. “This enables us to be lucky to witness our Sputnik moment: The challenge of widespread deployment of energy-efficient electronics impacting a broad range of applications, from efficient microwave transmission to long-range electric cars. I feel very fortunate to be able to contribute to this endeavor in a meaningful manner and, most importantly, have fun doing it with outstanding colleagues at UCSB.”

Mishra, the Donald W. Whittier Professor in Electrical Engineering, joined the UCSB faculty in 1990. He received his Ph.D. in electrical engineering from Cornell University and is an author of more than 800 publications, with more than 44,000 citations. A partial list of Mishra’s awards include the 2007 IEEE David Sarnoff Award, the 2007 International Symposium on Compound Semiconductors (ISCS) Quantum Device Award and the 2012 ISCS Heinrich Welker Award. Mishra also is an IEEE Fellow and a member of the National Academy of Engineering and the National Academy of Inventors.

The UCSB Current – "The Next Big Challenge" (full article)

Mishra's COE Profile

ECE Assistant Professor Yon Visell receives an NSF CAREER award for his haptics research

April 9th, 2018

visell at work in the lab
Visell is an advocate for more research into the physical mechanisms of human touch sensing – that can pave the way for new technologies of increasing relevance to modern society from wearables to robots to virtual and augmented reality

We use touch all of the time to interact with the world around us. Yet the sense of touch is far less understood than our other senses, such as vision and hearing. Our hands and brain gather a wealth of information as we interact with objects in our environment, but the ways in which this data is captured are something of a mystery.

“Recent research has shown that even lightly touching an object with a finger excites elastic waves that travel throughout the hand, eliciting responses in the sensory nervous system that evoke the conscious experience of touch,” said Visell, an assistant professor with appointments in UCSB’s Department of Electrical and Computer Engineering and in its Media Arts and Technology graduate program.“But the physical processes that are involved are as yet unclear.”

Now, with a National Science Foundation CAREER award, Visell aims to use his expertise in haptics — the science of communicating via touch — to shed light on its wave-like nature, with outcomes that could set the stage for advances in a wide array of fields, from engineering to neuroscience, medicine and education.

We greatly appreciate the support of the National Science Foundation, and in particular of the Cyber Human Systems program, for supporting our research on haptics — an area of growing importance that contains many surprising and enigmatic challenges,” Visell said. “Everyone has a lifetime of experience in interacting with the world via touch, yet our understanding of this important modality remains limited. We are excited to have the opportunity to expand our knowledge of haptics, and to create new engineering systems that make use of it.”

The UCSB Current – "Waves of Touch" (full article)

Visell's COE Profile

Visell's RE Touch Lab

UCSB honors ECE emeritus professor Larry Coldren, a giant in EE and materials science, for his work on PICs and tunable lasers

March 22nd, 2018

photo of coldren and kroemer
Some sixty people, including UC Santa Barbara faculty colleagues, alumni, and industry partners, convened at UCSB’s Loma Pelona Center on March 16 to honor Coldren

College of Engineering Dean Rod Alferness opened the event, titled “A History of PICs (Photonic Integrated Circuits) and VCSELs (Vertical Cavity Surface-Emitting Lasers),” before introducing Chancellor Henry Yang, who mentioned the following as just some of Coldren’s accomplishments.

He is a member of the National Academy of Engineering and the National Academy of Inventors, and a fellow of the Optical Society of America and the Institute for Electrical and Electronics Engineers. He was named to the latter before he even began the photonics work that would bring him worldwide renown. He spent thirteen years at Bell Labs, and came to UCSB in 1984, a move that one speaker described as “a risk he took that paid off; he saw UCSB as an up-and-coming university and wanted to help it grow.”

He spent two years as acting dean of the College of Engineering, was a co-founder of the Materials Department, and was named Fred Kavli Professor of Optoelectronics, making UCSB the first of now eighteen universities to host a Kavli Institute and named professor. He is part of the Institute for Energy Efficiency (IEE) at UCSB and has directed the Optoelectronics Technology Center, which he co-founded, since 1990.

Coldren has advised more than 70 PhD students, been issued more than 63 patents, and published more than a thousand papers, plus multiple book chapters and, in 1995, the seminal book Diode Lasers and Photonic Integrated Circuits, which has become a standard graduate-level text on the topic. His inventions have served as enabling technologies for some of the most widespread devices in the world, from iPhones to laser mice, to face recognition and fiber-optic networks. He cofounded two companies, Optical Concepts and Gore Photonics.

At the end of Chancellor Yang’s lengthy, but only partial, list of Coldren’s accomplishments, he said with a laugh, “I received one patent and it took ten years. I have no idea how Larry found the time to earn sixty-three and to do all the other things he did.”

Some 24 speakers including ECE professors Herb Kroemer, Art Gossard and John Bowers took the podium over several hours to honor Coldren’s legendary contributions.

COE News – "Honoring a Photonics Giant" (full article)

Coldren's COE Profile

Coldren's Optoelectronics Technology Center (OTC)

Forbes covers ECE Professor Kaustav Banerjee’s newly invented Kinetic Inductor

March 21st, 2018

forbes logo
Banerjee’s latest invention of a kinetic inductor that overcame a 200 year old fundamental limitation of the original device has received comprehensive coverage by the international business magazine Forbes

In an article titled, “The last barrier to ultra-miniaturized electronics is broken, thanks to a new type of inductor”, the magazine stated that with connected devices and the Internet of Things poised to become a multi-trillion dollar enterprise by the mid-2020s, this new type of inductor could be exactly the kind of revolution the burgeoning industry has been hoping for.

Since their invention in 1831 by the English scientist, Michael Faraday, all inductors had remained essentially the same in terms of their working principle that involved the magnetic inductance only. This, however, caused a fundamental scaling problem. In January this year, Professor Banerjee demonstrated a fundamentally new kind of inductor that exhibited sufficient kinetic inductance to beat the inherent limitations of the Faraday design for the very first time.

According to Forbes, due to this invention, next-generation communications, energy storage, and sensing technologies could be smaller, lighter, and faster than ever. Quite aptly, the article concludes, “And thanks to this great leap in nanomaterials, we might finally be able to go beyond the technology that Faraday brought to our world nearly 200 years ago”.

Founded in 1917, Forbes is the world’s leading business magazine. Published bi-weekly, it features original articles on finance, industry, investing, and marketing topics. Forbes also reports on related subjects such as technology, communications, science, politics, and law. The magazine is well known for its lists and rankings, including of the richest Americans (the Forbes 400), of the world’s top companies (the Forbes Global 2000), and The World’s Billionaires. Their digital site receives over 27 million visitors each month.

Forbes – "The Last Barrier to Ultra-Miniaturized Electronics is Broken, Thanks to a New Type of Inductor" (full article)

Banerjee's COE Profile

Banerjee’s Nanoelectronics Research Lab

ECE professors Jonathan Klamkin and Larry Coldren research on energy-efficient photonics-based circuits featured in The UCSB Current article “Shrinking SWaP”

March 8th, 2018

illustration of swap
Engineers receive a NASA grant to design smaller, lighter, cheaper and more energy-efficient photonics-based circuits

If the parts in a satellite, a drone or other specialized device are large in size, weight and power consumption — in other words, if their SWaP is high — the device itself has to be bigger and heavier and is usually more expensive to build, launch or operate.

With a new grant, UC Santa Barbara engineers Jonathan Klamkin and Larry Coldren aim to reduce SWaP to improve performance. The pair has received one of 12 highly competitive NASA research awards to produce low-SWaP integrated microphotonic circuits for satellite-based Lidar applications. The three-year award is part of NASA’s $14 million Advanced Component Technology Program.

Lidar is a light-based remote-sensing method that uses a pulsing laser to map environments. Ultra-low SWaP photonic integrated circuits (PICs) are intended for precise measurements of atmospheric constituents such as carbon dioxide.

“Photonic integrated circuits can reduce SWaP dramatically — by several orders of magnitude — so they can be deployed on smaller spacecraft that cost much less and launch more frequently,” said Klamkin, an associate professor in UCSB’s Department of Electrical and Computer Engineering. The upshot is significantly more scientific measurements at substantially reduced cost.

“We are shrinking down a very capable system from the size of a small refrigerator to pocket size and making it perform even better,” he added. “That opens up a lot of doors, not only for space missions but also for other applications. For space specifically, you could map Earth’s carbon dioxide — or methane or other gases — by putting our technology on CubeSats — modular satellites consisting of one or more 10-by-10-by-10-cm cubes. Today, systems like this don’t fit on even large satellites.”

The UCSB Current – “Shrinking SWaP” (full article)

To learn more read: UCSB College of Engineering News – "Smaller SWaP, Bigger Performance" (full article)

Coldren and Kamkin's Optoelectronics Technology Center (OTC)