Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New photodetector could improve night vision, thermal sensing and medical imaging

29.06.2018

UCLA's design eliminates tradeoffs between bandwidth, sensitivity, and speed that are common in current technology

Using graphene, one of science's most versatile materials, engineers from the UCLA Samueli School of Engineering have invented a new type of photodetector that can work with more types of light than its current state-of-the-art counterparts. The device also has superior sensing and imaging capabilities.


The photodetector operates across a broad range of light, processes images more quickly and is more sensitive to low levels of light than current technology.

Credit: UCLA Engineering

Photodetectors are light sensors; in cameras and other imaging devices, they sense patterns of elementary particles called photons, and create images from those patterns. Different photodetectors are built to sense different parts of the light spectrum. For example, photodetectors are used in night vision goggles to sense thermal radiation that is invisible to the naked eye. Others are used in cameras that identify chemicals in the environment by how they reflect light.

How versatile and useful photodetectors are depends largely on three factors: their operating speed, their sensitivity to lower levels of light, and how much of the spectrum they can sense. Typically, when engineers have improved a photodetector's capabilities in any one of those areas, at least one of the two other capabilities has been diminished.

The photodetector designed by the UCLA team has major improvements in all three areas - it operates across a broad range of light, processes images more quickly and is more sensitive to low levels of light than current technology.

"Our photodetector could extend the scope and potential uses of photodetectors in imaging and sensing systems," said Mona Jarrahi, a professor of electrical and computer engineering, who led the study. "It could dramatically improve thermal imaging in night vision or in medical diagnosis applications where subtle differences in temperatures can give doctors a lot of information on their patients. It could also be used in environmental sensing technologies to more accurately identify the concentration of pollutants."

The study was published in the journal Light: Science and Applications.

The new photodetector takes advantage of the unique properties of graphene, a super-thin material made up of a single layer of carbon atoms. Graphene is an excellent material for detecting photons because it can absorb energy from a broad swath of the electromagnetic spectrum -- from ultraviolet light to visible light to the infrared and microwave bands. Graphene is also a very good conductor of electrical current -- electrons can flow through it unimpeded.

To form the photodetector, the researchers laid strips of graphene over a silicon dioxide layer, which itself covers a base of silicon. Then, they created a series of comb-like nanoscale patterns, made of gold, with "teeth" about 100 nanometers wide. (A nanometer is one-billionth of a meter.)

The graphene acts as a net to catch incoming photons and then convert them into an electrical signal. The gold comb-shaped nanopatterns quickly transfer that information into a processor, which in turn produces a corresponding high-quality image, even under low-light conditions.

"We specifically designed the dimensions of the graphene nanostripes and their metal patches such that incoming visible and infrared light is tightly confined inside them," said Semih Cakmakyapan, a UCLA postdoctoral scholar and the lead author of the study. "This design efficiently produces an electrical signal that follows ultrafast and subtle variations in the light's intensity over the entire spectral range, from visible to infrared."

###

The study's other authors were UCLA graduate students Ping Keng Lu and Aryan Navabi.

The research was supported by the Department of Energy.

Amy Akmal | EurekAlert!
Further information:
http://newsroom.ucla.edu/releases/photodetector-improve-night-vision-thermal-sensing-medical-imaging

More articles from Power and Electrical Engineering:

nachricht Biologically inspired skin improves robots' sensory abilities (Video)
11.10.2019 | Technical University of Munich (TUM)

nachricht New electrolyte stops rapid performance decline of next-generation lithium battery
11.10.2019 | DOE/Argonne National Laboratory

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: An ultrafast glimpse of the photochemistry of the atmosphere

Researchers at Ludwig-Maximilians-Universitaet (LMU) in Munich have explored the initial consequences of the interaction of light with molecules on the surface of nanoscopic aerosols.

The nanocosmos is constantly in motion. All natural processes are ultimately determined by the interplay between radiation and matter. Light strikes particles...

Im Focus: Shaping nanoparticles for improved quantum information technology

Particles that are mere nanometers in size are at the forefront of scientific research today. They come in many different shapes: rods, spheres, cubes, vesicles, S-shaped worms and even donut-like rings. What makes them worthy of scientific study is that, being so tiny, they exhibit quantum mechanical properties not possible with larger objects.

Researchers at the Center for Nanoscale Materials (CNM), a U.S. Department of Energy (DOE) Office of Science User Facility located at DOE's Argonne National...

Im Focus: Novel Material for Shipbuilding

A new research project at the TH Mittelhessen focusses on the development of a novel light weight design concept for leisure boats and yachts. Professor Stephan Marzi from the THM Institute of Mechanics and Materials collaborates with Krake Catamarane, which is a shipyard located in Apolda, Thuringia.

The project is set up in an international cooperation with Professor Anders Biel from Karlstad University in Sweden and the Swedish company Lamera from...

Im Focus: Controlling superconducting regions within an exotic metal

Superconductivity has fascinated scientists for many years since it offers the potential to revolutionize current technologies. Materials only become superconductors - meaning that electrons can travel in them with no resistance - at very low temperatures. These days, this unique zero resistance superconductivity is commonly found in a number of technologies, such as magnetic resonance imaging (MRI).

Future technologies, however, will harness the total synchrony of electronic behavior in superconductors - a property called the phase. There is currently a...

Im Focus: How Do the Strongest Magnets in the Universe Form?

How do some neutron stars become the strongest magnets in the Universe? A German-British team of astrophysicists has found a possible answer to the question of how these so-called magnetars form. Researchers from Heidelberg, Garching, and Oxford used large computer simulations to demonstrate how the merger of two stars creates strong magnetic fields. If such stars explode in supernovae, magnetars could result.

How Do the Strongest Magnets in the Universe Form?

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International Symposium on Functional Materials for Electrolysis, Fuel Cells and Metal-Air Batteries

02.10.2019 | Event News

NEXUS 2020: Relationships Between Architecture and Mathematics

02.10.2019 | Event News

Optical Technologies: International Symposium „Future Optics“ in Hannover

19.09.2019 | Event News

 
Latest News

New material captures carbon dioxide

15.10.2019 | Materials Sciences

Drugs for better long-term treatment of poorly controlled asthma discovered

15.10.2019 | Interdisciplinary Research

Family of crop viruses revealed at high resolution for the first time

15.10.2019 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>