Nobel Prize winner C. V. Raman discovered in the 1920s that bombarding a substance with light excites its molecules and scatters the light in a signature pattern that can be analyzed like a fingerprint. Today Raman spectrometers are used in a variety of settings, but they tend to be large and expensive. A team led by physicist Manfred Fink of the University of Texas at Austin is developing a smaller, less expensive model that may improve earthquake detection and bring down the cost of some medical tests.
Fink’s device, which is about the size of a suitcase, does not measure the entire light spectrum but only one featured line containing the known signature for a target molecule. Inside the device, called the Analytic Non-Dispersive Raman Spectrometer, is a small diode laser whose light beam bounces between two concave mirrors to amplify its power. This light amplification also increases the sensitivity of the device, making it possible to measure impurities in parts per billion.
One aim would be to deploy the spectrometer in concert with seismographs to predict earthquakes as much as 45 minutes in advance. Seismographs have trouble distinguishing quake tremors from those that come from other sources, like construction. A spectrometer, however, could detect unusual proportions of gases released by seismic activity into hot springs and fissures in the ocean floor, which might indicate a coming quake.
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Other researchers are looking into medical applications for the device. Shirish Barve, a gastroenterologist at the University of Louisville, is testing whether it can monitor liver disease by analyzing patients’ breath, and Fink says the device may also be used to detect lactose intolerance in newborns.
