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Thermal noise of quantum IR detectors is defined by the number of thermal carriers with energy higher or equal to the
detector's energy threshold. The energy distribution function of these carriers is of Boltzmann-type with a high energy
tail dictated solely by the device temperature. Therefore, thermal noise in such detectors can be suppressed only by
cooling the device down.
Sirica presents new technology for tunable quantum IR detector that requires no cooling. The detection is based on the
response of non-equilibrium free carriers to IR photons. Sirica's IR detector uses pumping light (NIR/Visible) to form a
steady-state non-equilibrium distribution (SNED) of free carriers with a narrow high-energy tail (i.e. low effective
temperature), which is then used to absorb and detect IR photons. Simulations of the SNED formed in the case where
the free carrier's lifetime is shorter than their energy relaxation time is presented, showing that the free carriers' effective
temperature, is significantly lower than the device temperature.
Although the total number of carriers in the SNED formed is small, IR photon absorption coefficient in Sirica's detector
is very high (equivalent to MCT). This is due to the very high effective cross-section achieved in Sirica's proprietary
detector substance. Parameters of this composite structure will be discussed.
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