Photon Counting System

A photon is an elementary excitation of a single mode of quantized electromagnetic

radiation at a fixed point in space and time. The term photon was

named by Gilbert Lewis in 1926 for the first time, and it has been used ever since. This complicated tale begins with Einstein's vision of light as

an unbreakable collection of indivisible particles whose energy and momentum are

conserved throughout their interaction with matter and continues through the rest of

twentieth-century physics to the present day . In the intervening years, there has been a

lot of debate over the need and appropriateness of such a notion. British physicists Robert

Hanbury Brown and Richard Quentin Twiss presented an experiment in 1956, and this

experiment is one of the most recognized physics experiments today, known as the

Hanbury Brown and Twiss (HBT) experiment . The findings of HBT then questioned

and cast doubt on the idea of the photon hypothesis and asked for more research. Scientists

at that time were surprised by the conclusions of the HBT experiment, which initiated a

debate among the community of physicists that included Eric Brannen, Emil Wolf, Harry

Ferguson, Peter Fellgett, Lajos Janossy, Richard Sillitto, Leonard Mandel, and Edward

Purcell, as well as Hanbury Brown and Twiss themselves. In the 1950s, physicists

continued to think of photons as indivisible particles and wave packets, but the HBT

experiment prompted physicists to reconsider and reinterpret, or comprehend, the photon

concept for the first time .