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Laser Noise

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Definition: fluctuations of various parameters of laser light, such as the optical power and phase

German: Laserrauschen

Categories: fluctuations and noise, lasers

How to cite the article; suggest additional literature

Due to various influences of quantum noise and fluctuations of various technical origins, the output of a laser always contains some noise. There are different kinds of laser noise:

Origins of Laser Noise

The origins of laser noise can be divided into two groups:

Impacts of Laser Noise

Laser noise is important for many laser applications. Some examples are:

intensity noise spectrum

Figure 1: Intensity noise spectrum of a solid-state laser.

Methods for Noise Reduction

Laser noise can be reduced in many ways:

A prerequisite for effective noise reduction is that the origin of the most disturbing noise is known, in addition to the parameters determining the laser's sensitivity to thus noise influences. Depending on the case, it can be more effective to reduce either noise influences themselves or the laser's sensitivity.


[1]A. L. Schawlow and C. H. Townes, “Infrared and optical masers”, Phys. Rev. 112 (6), 1940 (1958)
[2]C. C. Harb et al., “Intensity-noise dependence of Nd:YAG lasers on their diode-laser pump source”, J. Opt. Soc. Am. B 14 (11), 2936 (1997)
[3]B. C. Buchler et al., “Feedback control of laser intensity noise”, Phys. Rev. A 57 (2), 1286 (1998)
[4]T. C. Ralph et al., “Understanding and controlling laser intensity noise”, Opt. Quantum Electron. 31, 583 (1999)
[5]R. Paschotta, “Noise of mode-locked lasers. Part I: numerical model”, Appl. Phys. B 79, 153 (2004); R. Paschotta, “Noise of mode-locked lasers. Part II: timing jitter and other fluctuations”, Appl. Phys. B 79, 163 (2004)
[6]R. Paschotta et al., “Optical phase noise and carrier–envelope offset noise of mode-locked lasers”, Appl. Phys. B 82 (2), 265 (2006)
[7]R. Paschotta, H. R. Telle, and U. Keller, “Noise of Solid State Lasers”, in Solid-State Lasers and Applications (ed. A. Sennaroglu), CRC Press, Boca Raton, FL (2007), Chapter 12, pp. 473–510
[8]R. Paschotta, “Noise in Laser Technology”. Part 1 – Intensity and Phase Noise; Part 2: Fluctuations in Pulsed Lasers; Part 3: Beam Pointing Fluctuations

(Suggest additional literature!)

See also: noise specifications, laser specifications, quantum noise, shot noise, intensity noise, phase noise, linewidth, Schawlow–Townes linewidth, amplifier noise, coherence, stabilization of lasers, mode hopping, Spotlight article 2006-08-01, Spotlight article 2006-08-20, Spotlight article 2006-10-09
and other articles in the categories fluctuations and noise, lasers

In the RP Photonics Buyer's Guide, 7 suppliers for low-noise lasers or equipment for the characterization of laser noise are listed.

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