Sensor awakens only in the presence of a signal of interest

phys.org | 9/12/2017 | Staff
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Here's your task. Build a tiny sensor that detects a signature of infrared (IR) wavelengths characteristic of a hot tailpipe, a wood fire, or perhaps even a human being. Design the sensor so that it can remain dormant and unattended but always alert, even for years, without drawing on battery power. And build the sensor so that the act of detection itself can initiate the emission of a signal that alerts warfighters, firefighters, or others that a "signal-of-interest" has been detected. It's just the sort of intelligence, reconnaissance, and surveillance (ISR) technology that can increase situational awareness while minimizing the need for potentially dangerous maintenance missions to replace run-down batteries.

Online today in the journal Nature Nanotechnology, a research team at Northeastern University, led by Electrical and Computer Engineering Associate Professor Matteo Rinaldi, reports pulling off this tall order of DARPA's Near Zero Power RF and Sensor Operation (N-ZERO) program with a device the Boston team refers to as a "plasmonically-enhanced micromechanical photoswitch."

Northeastern - IR - Sensor - Technology - Sensors

"What is really interesting about the Northeastern IR sensor technology is that, unlike conventional sensors, it consumes zero stand-by power when the IR wavelengths to be detected are not present," said Troy Olsson, manager of the N-ZERO Program in DARPA's Microsystems Technology Office. "When those IR wavelengths are present and impinge on the Northeastern team's IR sensor, the energy from the IR source heats the sensing elements which, in turn, causes physical movement of key sensor components. These motions result in the mechanical closing of otherwise open circuit elements, thereby leading to signals that the target IR signature has been detected."

The sensor is a showcase of clever physics and engineering, including a grid of nanoscale patches whose specific dimensions limit them to absorb only particular IR wavelengths. "The charge-based excitations, called plasmons (that can be thought of somewhat like...
(Excerpt) Read more at: phys.org
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