Background-limited performance BLIP

The photon noise is simply due to the uncertainty, a, in the number of photons per second, i.e., the detected signal level. In the photon noise limit the signal-to-noise ratio is proportional to the square root of the photon arrival rate. When the measured noise is the photon noise in the background radiation, the detection is said to have reached background limited performance (BLIP). 

BLIP (background-limited infrared jiiotodetecta-) sometimes means the best performance one can obtain - and that impUes QE-FF = 1.00. Here, we choose to express the best possible performance with a detector of any specified QE-FF product. 

The specific detectivity for the same diode is shown in Fig. 3.43. The same remark about the low efficiency of the structure is valid as above. However, even with such levels of improvement it can be seen that values of 4 x 10 cm Hz AV at 8.4 pm with cooling to 250 K can be reached. If extraction diodes with more complex profiles and with additional layers for performance improved are used, the values of specific detectivity under similar conditions exceed 10 cm Hz AV [386]. For the sake of comparison, the theoretical BLIP detectivity for a background at 300 K and radiating as blackbody is 6.24 x 10 ° cm Hz AV. The conclusion is that the performance of extraction detector, in spite of all limitations, approaches the BLIP limit. 

---