New micro-spectrometer can perform imaging exams on smartphone

Researchers from the Eindhoven University of Technology in the Netherlands recently presented in Nature Communications a spectrometer small enough to be inserted into a smartphone, according to an Eindhoven University of Technology release.  

The newly developed spectrometer contains capacity similar to normally sized models, making measurements through a "photonic crystal cavity trap," created by Zarko Zobenica, a PhD candidate at Eindhoven.  

"This trap is contained in a membrane, into which the captured light generates a tiny electrical current, and that is measured," according to the press release. "It is very precise, retaining just a very tiny frequency interval and therefore measuring only light at that frequency."   

Two of the membranes were placed closely one above the other, indefinitely influencing the other. Researchers—supervised by Andrea Fiore, PhD, professor at Eindhoven, and Rob van der Heijen, associate professor at Eindhoven—incorporated a micro-electromechanical mechanism (MEMS) to allow a varying distance between the membranes and overall measured frequency. The sensor is able to cover a wavelength of 30 nanometers made possible by the researchers being able to precisely determine the distance between the originally measured membranes to femtometers.  

Furthermore, the research team used a gas sensor to demonstrate the sensors usefulness. Fiore, though, explained it will take at least five years before the new spectrometer can be put into smartphones because of its small frequency range. 

"At the moment, the sensor covers just a few percent of the most common spectrum, the near-infrared, so his group will be working on extending the detectable spectrum," according to the press release. "They will also be integrating an extra element with the micro-spectrometer: a light source, which will make the sensor independent of external sources."