New miniature spectrometer will provide smartphones with tons of additional useful features

Thanks to the development of a new miniature spectrometer that is easy to manufacture and very small, it will be possible, using a smartphone or other portable electronic device that can be embedded in, to check the degree of air purity, freshness of food, blood sugar level or how toxic a piece is. something incomprehensible substance. This spectrometer, developed by experts from the Eindhoven University of Technology, boasts not only small dimensions, it provides measurement accuracy that matches the accuracy of normal tabletop spectrometers used in scientific laboratories.

Such a miniature size of the new spectrometer was obtained through the use of a “photonic crystal cavity”, a trap, several micrometers in size. It is arranged in such a way that the light trapped in this trap can never leave its limits. The trap is arranged in the volume of a thin membrane made of a special material that generates a small electric current due to the energy of absorbed photons. The precisely calculated dimensions of the trap allow it to capture photons of light, the wavelength of which is in a rather narrow range, and due to the narrowing of the frequency dynamic range, a high accuracy of the measurements is achieved.

To expand the frequency range, the researchers placed two membranes with two traps at a short distance from each other. These two membranes have a mutual influence, as a result of which the sensor can register light in twice the frequency range. The prototype sensor of the spectrometer operates in the range of 30 nanometers, within which it can distinguish with high accuracy about 100 thousand individual frequencies, and the distance between the two membranes of this sensor is only a few tens of femtometers (10 ^ -15 meters).

To demonstrate how the new spectrometer works, the researchers used it as a sensor in a gas analyzer. In addition, an extremely accurate motion sensor was created on the basis of the new spectrometer. However, the researchers believe that it will take them several more years to bring their development to the level of practical use. Currently, the frequency range of the spectrometer is only a few percent of the entire width of the near infrared spectrum, the coverage of which is required for all the functions mentioned at the beginning.

In addition to expanding the frequency range of the miniature spectrometer, the researchers plan to equip their device with an additional source of infrared light, which will make the device as a whole independent of external light sources

. Source: www.dailytechinfo.org