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Yes, modern CMOS image sensors have quantum efficiencies of more than 80 %, and modern CCDs are well above 90 %. This depends on wave length, particularly in th
by formerly_proven 4y ago
Yes, modern CMOS image sensors have quantum efficiencies of more than 80 %, and modern CCDs are well above 90 %. This depends on wave length, particularly in the NIR spectrum. This means that 80 or 90 % of the incident photons are converted into electrons. This number does not include photons being reflected from the surface of the sensor or the filter stack on top.
There's also SPADs "single photon avalanche diodes". These are sort of like a geiger counter for light, i.e. a single interacting photon triggers an impulse that can be counted or timed. These are very commonly used for time-of-flight sensors.
- wyager 4y agoNB that CMOS and CCD sensors might have a QE approaching 1, but they cannot (yet) be used to detect a single photon due to internal noise (unless you get a really expensive sensor and make it super cold). For detecting single photons, you need really high in-sensor amplification. Options include SPADs or photomultipliers if you don't need an image, or image intensifier tubes (used in night vision) if you do need an image. Semiconductor cameras that use IIT-like operational principles are in development now, undergoing testing for next-gen (digital) night vision.