Research Expertise and Interest

mechanical engineering, rapid prototyping, semiconductor manufacturing, photonics, micro-nano scale engineering, 3D fabrication technologies, microelectronics, micro and nano-devices, nano-lithography, nano-instrumentation, bio-MEMS

Research Description

The Zhang Lab is a highly interdisciplinary research group in nanoscience and engineering, with expertise in optical and electrical measurements, material synthesis, and theoretical modeling. Their research has primarily focused on the interaction of light with nanostructures, leading to exotic electromagnetic properties not found naturally. These phenomena have plentiful applications in photonics, imaging, energy, and others.

In the News

Heat energy leaps through empty space, thanks to quantum weirdness

If you use a vacuum-insulated thermos to help keep your coffee hot, you may know it’s a good insulator because heat energy has a hard time moving through empty space. Vibrations of atoms or molecules, which carry thermal energy, simply can’t travel if there are no atoms or molecules around. But a new study by researchers at the University of California, Berkeley, shows how the weirdness of quantum mechanics can turn even this basic tenet of classical physics on its head.

Scientists Push Valleytronics One Step Closer to Reality

Scientists at the Berkeley Lab have taken a big step toward the practical application of “valleytronics,” which is a new type of electronics that could lead to faster and more efficient computer logic systems and data storage chips in next-generation devices.

Opening a New Route to Photonics

A new route to ultrahigh density, ultracompact integrated photonic circuitry has been discovered by researchers with the  Lawrence Berkeley National Laboratory and UC Berkeley. The team has developed a technique for effectively controlling pulses of light in closely packed nanoscale waveguides, an essential requirement for high-performance optical communications and chip-scale quantum computing.

Tiny laser sensor heightens bomb detection sensitivity

A team of researchers at UC Berkeley have found a way to dramatically increase the sensitivity of a light-based plasmon sensor to detect incredibly minute concentrations of explosives. The sensor could potentially be used to sniff out a hard-to-detect explosive popular among terrorists.

Manipulating and Detecting Ultrahigh Frequency Sound Waves

An advance has been achieved towards next generation ultrasonic imaging with potentially 1,000 times higher resolution than today’s medical ultrasounds. Researchers with the DOE’s Lawrence Berkeley National Laboratory have demonstrated a technique for producing, detecting and controlling ultrahigh frequency sound waves at the nanometer scale.

Pushing innovations to industry's doorstep

A tiny laser that could enable smaller and faster smart phones and tablets. A glucosamine-like supplement that targets the underlying cause of multiple sclerosis. These are among research projects getting a boost this year from a UC grants program.

Flash of light switches right to left … for molecules

A research team that includes engineers from UC Berkeley and the Lawrence Berkeley National Laboratory has created a way to quickly change the left-right orientation of molecules, or chirality, with a beam of light. The development could be applied across a wide range of fields, including reduced energy use for data-processing, homeland security and ultrahigh-speed communications.

Invisibility cloak makes bumps disappear

It can’t quite cover Harry Potter, yet, but an invisibility cloak developed by UC Berkeley engineers was able to bounce visible light waves away from a microscopic object about as big as a red blood cell. The experiment using the reflective silicon oxide and silicon nitride material was described in the journal Nano Letters.

Graphene optical modulators could lead to ultrafast communications

UC Berkeley researchers have shown that graphene, a one-atom-thick layer of crystallized carbon, can be tuned electrically to modify the amount of photons absorbed. This ability to switch light on and off is the fundamental characteristic of a network modulator, opening the door to optical computing in handheld electronics.

Berkeley Lab Researchers Make First Perovskite-based Superlens for the Infrared

Berkeley Lab researchers have fabricated superlenses from perovskite oxides that are ideal for capturing light in the mid-infrared range, opening the door to highly sensitive biomedical detection and imaging. It may also be possible to turn the superlensing effect on/off, opening the door to highly dense data writing and storage.

Engineers take plasmon lasers out of deep freeze

UC Berkeley researchers have developed a new technique that allows plasmon lasers to operate at room temperature, overcoming a major barrier to practical utilization of the technology. Previous plasmon laser devices required temperatures as low as minus 450 degrees Fahrenheit to function properly.

Novel metamaterial vastly improves quality of ultrasound imaging

New "metamaterials" can overcome some of the limitations of microscopes and imagers, including ultrasound imagers. Researchers in the Nano-scale Science & Engineering Center have come up with a metamaterial to improve the picture quality of ultrasound by a factor of 50.

Featured in the Media

Please note: The views and opinions expressed in these articles are those of the authors and do not necessarily reflect the official policy or positions of UC Berkeley.
December 16, 2019
Karthik Sasihithlu
Debunking the longstanding assumption of physics that heat energy cannot pass through a vacuum, a team of scientists, including mechanical engineering professor Xiang Zhang and Hao-Kun Li, a former doctoral student in Professor Zhang's lab, has found that it can leap over a vacuum that is as much as 300 nanometers wide. The finding offers a range of new possibilities in thermal management at the nanoscale, and could be especially significant in the future development of high-speed computation and data storage technology. For more on this, see our press release at Berkeley News. Stories on this topic have appeared in dozens of sources around the world, including LiveScience and the FARS News Agency (Iran).
December 12, 2019
Amit Malewar
Heat energy can leap over two or three hundred nanometers of a vacuum, a team of Berkeley scientists has found, not only debunking one of physics' longstanding assumptions, but also suggesting new possibilities and considerations for manufacturers concerned with heat transfer. "Heat is usually conducted in a solid through the vibrations of atoms or molecules or so-called phonons -- but in a vacuum, there is no physical medium. So, for many years, textbooks told us that phonons could not travel through a vacuum," says mechanical engineering professor Xiang Zhang, the study's lead author. "What we discovered, surprisingly, is that phonons can indeed be transferred across a vacuum by invisible quantum fluctuations." Says first author Hao-Kun Li, a former doctoral student in Professor Zhang's lab: "This discovery of a new mechanism of heat transfer opens up unprecedented opportunities for thermal management at the nanoscale, which is important for high-speed computation and data storage. Now, we can engineer the quantum vacuum to extract heat in integrated circuits." For more on this, see our press release at Berkeley News. Stories on this topic have appeared in a couple dozen sources around the world, including NewScientist, Scientific American, Smart2.0 and Outlook India.
June 7, 2019
John Timmer
The Casimir effect, the quantum theory prediction that two metal plates will be attracted in a vacuum, has just gotten more complicated with the publication of a paper co-authored by mechanical engineering professor Xiang Zhang. The team found that the effect can also be repulsive, and that the balance between attractive and repulsive forces can cause a metal flake to levitate. "Before you get excited about riding a quantum hoverboard, it's important to emphasize that absolutely none of this scales up," the reporter notes. "This is one of those things that you have to accept is just pretty damn cool, rather than a gateway to obvious practical applications. ... That doesn't stop the authors from suggesting some less-than-obvious uses, such as 'contact-free nanomechanical systems and controlled self-assembly.' The latter is actually where this could turn out to be useful. As we've started exploring the value of various nanoparticles, the Casimir effect can actually be a problem, causing these tiny particles to aggregate rather than dispersing through a suspension. It is possible that we could design a tiny coating that preserves the nanoparticles' features while allowing them to repel each other if they get too close." For more on this, see the story at Berkeley Engineering. Another story on this topic appeared in Physics World.
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