Homogeneous Broadening
Definition: the increase in the linewidth of an atomic transition caused by effects which affect different radiating or absorbing atoms in the same way
German: homogene Verbreiterung
Category: physical foundations
How to cite the article; suggest additional literature
Author: Dr. Rüdiger Paschotta
Homogeneous broadening, as opposed to inhomogeneous broadening, refers to effects which increase the optical linewidth of an electronic transition by equally affecting different radiating or absorbing atoms, ions or molecules. The spectral shape of the transition cross sections of all involved atoms are then equal.
Some common cases with homogeneous broadening are as follows:
- Isolated non-moving atoms or ions exhibit transitions with a natural linewidth, resulting from the finite lifetimes of the energy levels involved.
- In a gas (e.g. of a gas laser), all atoms or molecules of some species experience the same average rate of collisions, which lead to collisional broadening.
- In many laser crystals, laser-active ions can occupy only one type of site in the crystal lattice. (This applies e.g. to Nd3+ ions in Nd:YAG.) The interaction of such ions with the crystal lattice via phonons then affects all these ions equally. Rapid transitions between the sublevels of the involved Stark level manifolds lead to strongly reduced sublevel lifetimes, and thus to linewidth values which are orders of magnitude larger than the natural linewidth as expected from the lifetimes of the whole Stark level manifolds.
Homogeneous broadening is strongly related to homogeneous saturation in laser gain media.
Questions and Comments from Users
Here you can submit questions and comments. As far as they get accepted by the author, they will appear above this paragraph together with the author’s answer. The author will decide on acceptance based on certain criteria. Essentially, the issue must be of sufficiently broad interest.
Please do not enter personal data here; we would otherwise delete it soon. (See also our privacy declaration.) If you wish to receive personal feedback or consultancy from the author, please contact him e.g. via e-mail.
By submitting the information, you give your consent to the potential publication of your inputs on our website according to our rules. (If you later retract your consent, we will delete those inputs.) As your inputs are first reviewed by the author, they may be published with some delay.
See also: linewidth, inhomogeneous broadening, gain bandwidth, gain saturation
and other articles in the category physical foundations
 |
If you like this page, please share the link with your friends and colleagues, e.g. via social media:
These sharing buttons are implemented in a privacy-friendly way!