Photonics is the science and technology of generating, controlling, and detecting photons, which are particles of light.

Note that in a perfectly dark room the eye can detect single photons but, of course, single photons are not sufficient to form an image.

Even a molecule at absolute zero may detect random photons flying through the air, an occasional stray electron.

The sensors are so sensitive that they need only very little light and can even detect single photons.

The goals of the telescope are to detect and study primarily photons coming from:

The radiation from the base overwhelmed the equipment that the researchers had hoped would detect single photons coming from the dots.

For the corresponding Poissonian distribution, the probability of detecting photons is:

These are made from doped silicon and depend on the avalanche breakdown effect to detect even single photons.

In either case, the photomultiplier can detect individual photons.

Nonetheless, the ability to detect single photons striking the primary photosensitive surface itself reveals the quantization principle that Einstein put forth.