Plasmonic photoswitch sensor consumes no power unless IR signal is present

Oct. 12, 2017
An infrared sensor based on a plasmonically enhanced micromechanical photoswitch remains dormant with near-zero power consumption until awakened by an external trigger or stimulus.

To satisfy the requirements of the Defense Advanced Research Projects Agency (DARPA; Arlington, VA) Near Zero Power RF and Sensor Operations (N-ZERO) program with a goal of developing reliable sensors that improve warfighter safety, researchers at Northeastern University (Boston, MA) have developed an infrared (IR) sensor based on a plasmonically enhanced micromechanical photoswitch that does precisely what N-ZERO demands: remain dormant with near-zero power consumption until awakened by an external trigger or stimulus—in this case, a heat source that could be a potential threat.

The new type of photoswitch essentially consists of a light-actuated microelectromechanical (MEM) relay that, through a plasmonically enhanced thermomechanical coupling mechanism, harvests the energy in a specific spectral band of light and uses it to mechanically create a conducting channel between the device terminals only when that specific light is present, enabling near-zero power consumption in the standby mode. The plasmonically enhanced micromechanical photoswitches (PMPs) are sensitive to only a narrow spectral signal, thanks to photolithographically engineered plasmonic nanostructures. When IR radiation matching the absorption band defined by the nanostructures is absorbed and converted to heat, it causes a downward bend in the thermally sensitive bimaterial legs of the device and a vertical displacement of a metal tip that then touches the opposite terminal, creating a conductive channel when the IR power exceeds the designed threshold level. Multiple PMPs can be engineered on the same chip to detect different IR signals such as tailpipe combustion signals, burning wood in a forest fire, or possibly the presence of human heat energy. Reference: Z. Qian et al., Nature Nanotechnol. online, doi:10.1038/nnano.2017.147 (Sep. 11, 2017).

About the Author

Gail Overton | Senior Editor (2004-2020)

Gail has more than 30 years of engineering, marketing, product management, and editorial experience in the photonics and optical communications industry. Before joining the staff at Laser Focus World in 2004, she held many product management and product marketing roles in the fiber-optics industry, most notably at Hughes (El Segundo, CA), GTE Labs (Waltham, MA), Corning (Corning, NY), Photon Kinetics (Beaverton, OR), and Newport Corporation (Irvine, CA). During her marketing career, Gail published articles in WDM Solutions and Sensors magazine and traveled internationally to conduct product and sales training. Gail received her BS degree in physics, with an emphasis in optics, from San Diego State University in San Diego, CA in May 1986.

Voice your opinion!

To join the conversation, and become an exclusive member of Laser Focus World, create an account today!