An angle-sensitive pixel (ASP) is a CMOS light sensor which is sensitive to the incoming light that is striking the sensor at a sinusoidal incident angle.

Most ASPs are composed of two gratings

•          A diffraction grating

•          An analyzer grating

And make use of two known effects

•          The Moire effect

•          The Talbot effect

If we consider light as a particle, then at certain incident angles the light passes the diffraction gratings but gets stopped by the analyzer grating. Which means that the amount of light reaching the photodiode placed above the two gratings would be proportional to a sinusoidal function of incident angle, as the two gratings come in and out of phase with each other with shifting incident angle. By building ASPs where the vertical separation between the gratings is approximately equal to a half-integer multiple of the Talbot depth, the sinusoidal sensitivity with incident angle is observed.

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