Path: EDN Asia >> News Centre >> Industrial/Mil/Aero >> Photosensor sees colour like human eyes
Industrial/Mil/Aero Share print

Photosensor sees colour like human eyes

04 Sep 2014  | Jade Boyd

Share this page with your friends

Zheng's colour photodetector uses a combination of band engineering and plasmonic gratings, comb-like aluminium structures with rows of parallel slits. Using electron-beam evaporation, which is a common technique in CMOS processing, Zheng deposited a thin layer of aluminium onto a silicon photodetector topped with an ultrathin oxide coating.

Biomimetic colour photodetector

Rice University's new biomimetic colour photodetector uses aluminium gratings like the one in this image from a scanning electron microscope. The light-filtering slits in the grating are about 100nm wide. (Source: B. Zheng/Rice University)

Colour selection is performed by utilising interference effects between the plasmonic grating and the photodetector's surface. By carefully tuning the oxide thickness and the width and spacing of the slits, Zheng was able to preferentially direct different colours into the silicon photodetector or reflect it back into free space.

The metallic nanostructures use surface plasmons—waves of electrons that flow like a fluid across metal surfaces. Light of a specific wavelength can excite a plasmon, and LANP researchers often create devices where plasmons interact, sometimes with dramatic effects.

"With plasmonic gratings, not only do you get colour tunability, you can also enhance near fields," Zheng said. "The near-field interaction increases the absorption cross section, which means that the grating sort of acts as its own lens. You get this funnelling of light into a concentrated area.

"Not only are we using the photodetector as an amplifier, we're also using the plasmonic colour filter as a way to increase the amount of light that goes into the detector," he said.

Co-authors include Rice graduate student Yumin Wang and Peter Nordlander, professor of physics and astronomy at Rice. The research was supported by the Office of Naval Research, the Department of Defense's National Security Science and Engineering Faculty Fellowship Program and the Robert A. Welch Foundation.


 First Page Previous Page 1 • 2


Want to more of this to be delivered to you for FREE?

Subscribe to EDN Asia alerts and receive the latest design ideas and product news in your inbox.

Got to make sure you're not a robot. Please enter the code displayed on the right.

Time to activate your subscription - it's easy!

We have sent an activate request to your registerd e-email. Simply click on the link to activate your subscription.

We're doing this to protect your privacy and ensure you successfully receive your e-mail alerts.


Add New Comment
Visitor (To avoid code verification, simply login or register with us. It is fast and free!)
*Verify code:
Tech Impact

Regional Roundup
Control this smart glass with the blink of an eye
K-Glass 2 detects users' eye movements to point the cursor to recognise computer icons or objects in the Internet, and uses winks for commands. The researchers call this interface the "i-Mouse."

GlobalFoundries extends grants to Singapore students
ARM, Tencent Games team up to improve mobile gaming


News | Products | Design Features | Regional Roundup | Tech Impact