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The Photonics Spotlight

Saturation of Pump Absorption - An Important Issue?

Posted on 2007-08-22 as a part of the Photonics Spotlight (available as e-mail newsletter!)

Permanent link: https://www.rp-photonics.com/spotlight_2007_08_22.html

Author: Dr. Rüdiger Paschotta, RP Photonics Consulting GmbH

Abstract: Pump saturation effects in laser gain media are often ignored. In many cases, this can be justified, because such effects are rather weak. However, this is not always the case. The article illustrates this with some examples.

Dr. Rüdiger Paschotta

Ref.: encyclopedia articles on pump absorption

When saturation in lasers or amplifiers is discussed, this happens most often in the context of gain saturation. However, there can also be saturation of pump absorption: the efficiency of pump absorption (and thus also the wall-plug efficiency) can be reduced, essentially by bleaching of the ground state population of the laser-active ions or atoms.

The question is then whether such effects are strong enough to be worth consideration. Here are some thoughts:

These examples show that a general statement on the importance of pump saturation effects should not be made. Often enough, you may ignore such effects, but it is good to know where.

This article is a posting of the Photonics Spotlight, authored by Dr. Rüdiger Paschotta. You may link to this page and cite it, because its location is permanent. See also the Encyclopedia of Laser Physics and Technology.

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