View source for Photon noise

{{Sources exist|date=October 2019}}
'''Photon noise''' is the randomness{{Citation needed|date=October 2019}} in signal associated with [[photon]]s arriving at a detector.  For a simple [[black body]] emitting on an absorber, the [[noise-equivalent power]] is given by

:<math>\mathrm{NEP}^2 = 2 h^2 \nu^2 \Delta\nu \left( \frac{n}{\eta} + n^2 \right)</math>

where <math>h</math> is the [[Planck constant]], <math>\nu</math> is the central frequency, <math>\Delta\nu</math> is the bandwidth, <math>n</math> is the [[occupation number]] and <math>\eta</math> is the optical efficiency.

The first term is essentially [[shot noise]] whereas the second term is related to the [[boson]]ic character of photons, variously known as "[[Satyendra Nath Bose|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==
* [[Hanbury Brown and Twiss effect]]
* [[Phonon noise]]

==References==
*{{Citation
| last1 = Hanbury Brown
 | first1 = R.
 | last2 = Twiss
 | first2 = R. Q.
 | title = Interferometry of the intensity fluctuations in light - I. Basic theory: the correlation between photons in coherent beams of radiation
 | journal = Proceedings of the Royal Society A
 | volume = 242
 | issue = 1230
 | pages = 300–324
 | date = 5 November 1957}}
*{{cite journal
 | last = Boyd
 | first = Robert W.
 | title = Photon Bunching and the Photon-Noise-Limited Performance of Infrared Detectors 
 | journal = Infrared Physics
 | volume = 22
 | issue = 3
 | pages = 157–162
 | date = May 1982| doi = 10.1016/0020-0891(82)90034-3
 | bibcode = 1982InfPh..22..157B
 }}
*{{cite journal
 | last = Zmuidzinas
 | first = Jonas
 | title = Thermal noise and correlations in photon detection
 | journal = Applied Optics
 | volume = 42
 | issue = 25
 | pages = 4989–5008
 | date = 2003| doi = 10.1364/AO.42.004989
 | pmid = 12962374
 | bibcode = 2003ApOpt..42.4989Z
 | url = https://authors.library.caltech.edu/8954/
 }}

==Further reading==
*{{cite web |url= https://people.csail.mit.edu/hasinoff/pubs/hasinoff-photon-2012-preprint.pdf |title=Photon, Poisson noise |last=Hasinoff |first=Samuel W. |date= |website= |publisher= |access-date= 17 December 2019 |quote=}}

[[Category:Photons]]
[[Category:Energy]]

[[Category:Signal processing]]
[[Category:Particle statistics]]
[[Category:Photodetectors]]


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