Page "Photon" Paragraph 5

In physics, a photon is usually denoted by the symbol γ ( the Greek letter gamma ).

This symbol for the photon probably derives from gamma rays, which were discovered in 1900 by Paul Villard, named by Ernest Rutherford in 1903, and shown to be a form of electromagnetic radiation in 1914 by Rutherford and Edward Andrade.

In chemistry and optical engineering, photons are usually symbolized by hν, the energy of a photon, where h is Planck's constant and the Greek letter ν ( nu ) is the photon's frequency.

Much less commonly, the photon can be symbolized by hf, where its frequency is denoted by f.