Nanoparticle Infrared Detector Is Ultrasensitive, Cheap

Continued from page 1

Sargent says infrared cameras based on InGaAs chips now cost $40,000 to $60,000, whereas his technology could lead to much cheaper cameras. The cost of coating a square meter with the quantum dot solution is $17, he says, and speculates that infrared cameras might one day cost as little as today's digital cameras.

Such a dramatic cost reduction could be a boon for those developing infrared imaging for medical diagnosis. Infrared imaging should be able to penetrate centimeters into tissue. Like X-ray imaging, it could be used for medical diagnosis. Researchers at MIT and Harvard University, for example, have developed an infrared imaging technology to detect cancer during surgery. The infrared rays, which have lower energy than visible light, pose no risk to surgeons and nurses and could help ensure that all of a tumor is removed. This technology uses the near-infrared; Sargent says tissue has even greater transparency to SWIR light. (The Massachusetts researchers are led by John Frangioni, associate professor of medicine at Boston's Beth Israel Deaconess Medical Center and Moungi Bawendi, MIT chemistry professor and a pioneer in quantum dot research.)

The chips could also be integrated into night-vision goggles, likely at the same price as existing near-infrared detectors. According to Sargent, they shouldn't come with higher manufacturing costs or require more power. In contrast, InGaAs chips are too expensive for widespread use and require extra battery power to keep them cool.

But whatever its future uses, says Peter Peumans, assistant professor of electrical engineering at Stanford University, Sargent's device "confirms that nanostructuring is a way to improve device performance."