Politecnico di Milano: A New Dual-Band Detector

A dual-band infrared detector for numerous applications such as vision in adverse weather conditions (with the presence of smoke, fog or mist), material recognition, analysis of the paint layers of a painting, or the identification of counterfeit banknotes. This is the result of a study conducted by researchers at the Physics Department of the Politecnico di Milano, led by Prof. Giovanni Isella, together with researchers at the German Forschungszentrum Jülich (FZJ), presented in the journal ACS Photonics.

Compared to the devices currently on the market, the proposed devices will use cheaper materials – such as germanium and tin – and will be made using processes that are compatible with the same manufacturing techniques already used in the microelectronics sector, thus making it possible to obtain compact miniaturised spectrometers without mechanical components at a considerably lower cost.

This paves the way for interesting new applications of infrared imaging in areas such as the automotive, home security and machine vision sectors.

The new detector is able to provide, without the use of filters or other optical elements, two spectrally different but complementary images of the same object, due to its ability, when varying the sign of the applied polarisation voltage, to provide a spectral response that can be toggled between the two bands of near-infrared (NIR) and short-wave infrared (SWIR).