Princeton engineers have developed a sensor, seen in this micrograph, that gathers and amplifies Raman signals, which are wavelengths of light that can be used to identify substances. The sensor relies on a newly designed chip studded with uniform rows of tiny pillars made of metals and insulators. (Photo by Stephen Chou)
Princeton researchers have invented an extremely sensitive sensor that opens up new ways to detect a wide range of substances, from biological markers of cancer to hidden explosives. The sensor, which is the most sensitive of its kind to date and easy to produce, relies on a completely new architecture and fabrication technique developed by the Princeton researchers. The device boosts faint signals generated by the scattering of laser light from a material placed on the sensor, allowing the identification of various substances based on the color of light they reflect. The sample could be as small as a single molecule. The technology is a major advance in a decades-long search to identify materials using Raman scattering, a phenomena discovered in the 1920s by Indian physicist Chandrasekhara Raman, in which light reflecting off an object carries a signature of its molecular composition and structure. "Raman scattering has enormous potential in biological and chemical sensing, and could have many applications in industry, medicine, the military and other fields," said Stephen Chou , the professor of electrical engineering who led the research team. "But current Raman sensors are so weak that their use has been very limited outside of research.
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