Photon noise

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Photon noise is the randomness[citation needed] in signal associated with photons arriving at a detector. For a simple black body emitting on an absorber, the noise-equivalent power is given by

where is the Planck constant, is the central frequency, is the bandwidth, is the occupation number and is the optical efficiency.

The first term is essentially shot noise whereas the second term is related to the bosonic character of photons, variously known as "Bose noise" or "wave noise". At low occupation number, such as in the visible spectrum, the shot noise term dominates. At high occupation number, however, typical of the radio spectrum, the Bose term dominates.

See also[edit]


  • Hanbury Brown, R.; Twiss, R. Q. (5 November 1957), "Interferometry of the intensity fluctuations in light - I. Basic theory: the correlation between photons in coherent beams of radiation", Proceedings of the Royal Society A, 242 (1230): 300–324
  • Boyd, Robert W. (May 1982). "Photon Bunching and the Photon-Noise-Limited Performance of Infrared Detectors". Infrared Physics. 22 (3): 157–162. Bibcode:1982InfPh..22..157B. doi:10.1016/0020-0891(82)90034-3.
  • Zmuidzinas, Jonas (2003). "Thermal noise and correlations in photon detection". Applied Optics. 42 (25): 4989–5008. Bibcode:2003ApOpt..42.4989Z. doi:10.1364/AO.42.004989. PMID 12962374.

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