RP Photonics logo
RP Photonics
Encyclopedia
Technical consulting services on lasers, nonlinear optics, fiber optics etc.
Profit from the knowledge and experience of a top expert!
Powerful simulation and design software.
Make computer models in order to get a comprehensive understanding of your devices!
Success comes from understanding – be it in science or in industrial development.
The famous Encyclopedia of Laser Physics and Technology – available online for free!
The ideal place for finding suppliers for many photonics products.
Advertisers: Make sure to have your products displayed here!
… combined with a great Buyer's Guide!
VLib part of the
Virtual
Library

Clustering

<<<  |  >>>

Definition: the tendency e.g. of laser-active ions in laser gain media to form clusters in their host medium

Category: optical materials

How to cite the article; suggest additional literature

In the context of laser physics, clustering is the tendency of laser-active ions in a solid-state gain medium to form clusters rather than to be randomly spread. This is normally an undesirable effect, as it allows for energy transfer between laser ions which can seriously degrade the gain and power efficiency by processes which are called quenching. For example, this can occur in erbium-doped gain media with high erbium concentration (e.g. in some erbium-doped fiber amplifiers). Here, there are e.g. energy transfers involving two erbium ions which are initially in the upper laser level, where then one ion reaches the ground state and transfers its energy to the second ion. The latter ion will quickly relax to the upper laser level, and effectively one of the two excitations is lost. The (often weak) population of a high-lying state leads to some upconversion fluorescence.

The simplest way to avoid clustering is to keep the doping concentration low. However, high doping concentrations are desirable in some situations, e.g. when a short fiber laser or amplifier must be constructed. In that case, it is important to select a host material with a high solubility of the dopant. For example, phosphate glasses allow for higher erbium concentrations without clustering, compared with silicate glasses.

See also: gain media, quenching, upconversion, energy transfer, doping concentration
and other articles in the category optical materials

If you like this article, share it with your friends and colleagues, e.g. via social media:

arrow