Position-sensing detectors characteristics

Silicon photodetectors are commonly used for light power measurements in a wide range of applications such as bar-code readers, medical imaging, spectroscopy, and laser printers.  There is another function, however, which utilises the photodetectors as optical position sensors. They are widely referred to as Position Sensing Detectors (PSDs). The applications vary from human eye movement monitoring, 3D modelling of human motion to laser, light source, and mirrors alignment. They are also widely used in ultra-fast, accurate autofocusing schemes for a variety of optical systems, such as microscopes, machine tool alignment, vibration analysis, and more.