Raman spectrometer detects trace chemicals in real time

According to a statement, the new sensor’s compact design makes it practical for rapid field deployment to disaster zones and areas with security concerns.

Raman spectrometers use highly focused beams of light at precise wavelengths to illuminate small samples of materials.

Very sensitive detectors then study the spectra of light that has been re-emitted, or scattered, by the sample.

Most of this scattered light retains its original frequency or colour, but a very small percentage of that light is shifted ever so slightly to higher or lower wavelengths, depending on the vibrational modes of the sample being studied.

By comparing the shifted and the original wavelengths, it is possible to determine the precise chemicals present in the sample.

The researchers brought this capability down to size by constructing their Raman spectrometer using a low-power, low-cost commercial green laser pointer.

The green laser’s relatively short wavelength helped to improve the detection of the inherently weak Raman signal.