Discovery History of Photon

The history of the prediction and discovery of the photon rank among the most fascinating chapters of twentieth century science.

The photon is known as the quantum of electromagnetic radiation. In physics, a quantum is a basic indivisible unit or state that may be present or absent but never stronger or weaker.

In 1905, Albert Einstein published a paper describing his discovery of the photoelectric effect where a photon acts like a particle.

But before that in 1900, the Russian physicist Peter Lebedew experimentally measure photon radiation measure.

In 1901 new formula by Plank was established for radiation of a black body and introduction of what was later called the quantum of action.

In 1902 Lenard discovered that energy of electrons in photo-effect does not depend on the intensity of light but depends on the wavelength of the latter.

Einstein proposed that for some purposes light can be regarded as made up of photon particles. He published a paper describing his discovery of the photoelectric effect where a photon acts like a particle, thereby supporting and augmenting Planck’s quantization discovery.

In 1909 and 1916, Einstein showed that, if Planck's law of black-body radiation is accepted, the energy quanta must also carry momentum , making them full-fledged particles. Einstein incorporated photon momentum into quantum mechanics.

The term ‘photon’ for particles of light was coined by Lewis in 1926 in an article ‘The Conservation of Photons’. He considered photons to be ‘atoms’ of light.

The 1921 physics Nobel prize was awarded to Einstein in most famous for his theory of relativity, but it is his discovery of photons that is mentioned by the Swedish Academy.

This photon momentum was observed experimentally by Arthur Holly Compton, for which he received the Nobel Prize in 1927.

He verified experimentally by Milikan’s studies of the photoelectric effect in 1914 – 16.
Discovery History of Photon