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Stabilization of Lasers

Definition: measures applied to lasers in order to improve their stability in terms of output power, optical frequency, or other quantities

German: Stabilisierung von Lasern

Categories: laser devices and laser physicslaser devices and laser physics, fluctuations and noisefluctuations and noise, methodsmethods


Cite the article using its DOI: https://doi.org/10.61835/fkd

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As lasers exhibit various kinds of laser noise, which can be detrimental in applications, it is sometimes necessary to use techniques for suppressing noise and stabilizing certain laser parameters. There are active and passive stabilization schemes, as discussed in the following. Concerning frequency stabilization, see the article on frequency-stabilized lasers for more details.

See also the article on synchronization of lasers, which treats both timing and phase synchronization.

Active Laser Stabilization

Active stabilization schemes usually involve some kind of electronic feedback (or sometimes feedforward) system, where fluctuations of some parameters are converted to an electronic signal, which is then used to act on the laser in some way.

Examples are:

  • The output power of a laser may be stabilized with a scheme as shown in Figure 1. The laser power is monitored with a photodiode and corrected e.g. via control of the pump power or the losses in or outside the laser resonator. In this way, both spiking after turn-on and the intensity noise under steady-state conditions can be reduced.
  • Note that it is also possible to reduce intensity noise by acting on the output beam instead of the laser itself; see the article on noise eaters.
power stabilization for a laser
Figure 1: Diode-pumped solid-state laser with a feedback system stabilizing the output power.

The stability which is achieved with such active systems is determined by factors such as photodetection noise, the bandwidth of control elements, the design of the feedback electronics, and the stability of the reference standards (e.g. optical reference cavities).

Passive Laser Stabilization

Passive schemes do not involve electronics and are based on purely optical effects. Examples are:

The optical frequency of a laser may also be stabilized by injection locking, i.e., injecting a beam with a highly stable optical frequency from another laser.

More to Learn

Encyclopedia articles:


The RP Photonics Buyer's Guide contains 17 suppliers for laser stabilization devices. Among them:


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(Suggest additional literature!)

Questions and Comments from Users


What metrics are commonly used to quantify stability?

The author's answer:

Typically, one would quantify the opposite – noise. For example, it might be the relative intensity noise quantified in dBm/Hz or a linewidth in Hz.

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