Determination of the Number of Photons Absorbed in SiO2/W/FeSb2/W Detection Pixel of Thermoelectric Single-Photon Detector

The results of modeling heat propagation processes in the four-layer SiO 2 /W/FeSb 2 /W detection pixel of thermoelectric single-photon detector after absorbing more than one IR photon are presented. The calculations were carried out by a three-dimensional matrix method for partial differential equations. The cases of both simultaneous absorption of several photons on a 1-μm segment of the absorber surface and the absorption of photons following with a certain time delay are investigated. It is shown that the decay time of the detector signal to the background value substantially depends on the number of simultaneously absorbed photons. Using this parameter, you can determine the number of absorbed photons up to eight. The SiO 2 /W/FeSb 2 /W detection pixel can also register photons following with a time delay of 5 fs, which corresponds to a counting rate of 2 × 10 14 Hz. A detector with such characteristics is in demand in many areas of modern technology.