The new compact infrared detector to reveal counterfeiters

ACS Photonics magazine featured a dual-band infrared detector with applications in many fields, such as vision in adverse weather conditions (fog, mist, presence of smoke), analysis of paint layers, recognition of materials and identification of counterfeit banknotes.

It was developed by researchers from the Physics Department of the Politecnico of Milan, under the guidance of professor Giovanni Isella, with the collaboration of researchers from the German center Forschungszentrum Jülich.

This compact miniaturized spectrometer has a double advantage compared to the instruments already existing on the market, which allows to maintain lower costs: it can be built with cheaper materials (such as germanium and tin) and can be achieved through processes compatible with techniques already existing in the microelectronics field.

HOW DOES THE INFRARED DETECTOR WORKS?

The detector is integrated on a silicon chip and is able to show, without using filters or other additional optical elements, two spectrally different but complementary images of the same object .

This process is possible thanks to the ability, as the sign of the applied bias voltage varies, to provide a switchable spectral response between the two bands of near infrared (NIR) and short wave infrared (SWIR).

The study thus introduces new applications of infrared technology in various fields, such as automotive, home security and machine vision.  

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