photodetector

instrument

Also known as: photosensor

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Last updated

July 2, 2026

Quick Summary

A photodetector is an instrument that measures the intensity of radiant energy, such as light, through photoelectric action. These devices convert electromagnetic radiation, from ultraviolet to infrared and visible light, into an electrical signal.12

Photodetectors are employed in various applications, including photography, measuring glare, and in more complex instruments like spectrographs and telescopes. Different types of photodetectors exist, such as photoemissive detectors (like photomultiplier tubes) and solid-state detectors (like photodiodes and charge-coupled devices or CCDs). These technologies enable the detection and measurement of light, from counting individual photons to capturing spatial variations of light for imaging.23

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…solid-state scanner that has 1,728 photosensors in a single row. Each photosensor in turn generates a low or high variation in voltage, depending on whether the scanned spot is black or white. Since there normally are 4 scan lines per mm (100 scan lines per inch), the scanning of a…
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…solid-state scanner that has 1,728 photosensors in a single row. Each photosensor in turn generates a low or high variation in voltage, depending on whether the scanned spot is black or white. Since there normally are 4 scan lines per mm (100 scan lines per inch), the scanning of a…
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spectroscopy
Diffraction
An electronic photodetector placed behind the slit can then be used to measure the amount of light in each part of the spectrum. The advantage of such an arrangement is that photodetectors are extremely sensitive, have a fast time response, and respond linearly to the energy of…
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An electronic photodetector placed behind the slit can then be used to measure the amount of light in each part of the spectrum. The advantage of such an arrangement is that photodetectors are extremely sensitive, have a fast time response, and respond linearly to the energy of…
Read More