Encyclopedia … combined with a great Buyer's Guide!

Inhomogeneous Broadening

Definition: the increase in the linewidth of an atomic transition caused by effects which act differently on different radiating or absorbing atoms

German: inhomogene Verbreiterung

Category: physical foundations

Author:

How to cite the article; suggest additional literature

URL: https://www.rp-photonics.com/inhomogeneous_broadening.html

Inhomogeneous broadening is an increase in the linewidth of an atomic transition caused by effects which cause different radiating or absorbing atoms (or ions) to interact with different wavelength components. (Examples of such effects are discussed below.) This means that the absorption and emission cross-sections have different spectral shapes for different atoms. The fluorescence spectrum from such a material can then exhibit peaks which are broader than those of single atoms, since it shows an average over many differently emitting atoms. In similar ways, absorption spectra can be broadened.

Inhomogeneous broadening can be caused in various ways:

  • Different velocities of the atoms of a gas (e.g. in a gas laser) cause different Doppler shifts (→ Doppler broadening).
  • In a solid medium, there can be different lattice locations e.g. of laser-active ions, where the ions experience different local electric and magnetic fields. This is particularly the case for glasses, but can also occur in crystalline materials (particularly in disordered crystals).

Inhomogeneous broadening is strongly related to inhomogeneous saturation in laser gain media.

See also: linewidth, inhomogeneous saturation, homogeneous broadening, laser gain media, gain bandwidth

Questions and Comments from Users

2020-03-17

Which kind of gain medium can cause multiple longitudinal modes oscillating simultaneously in the cavity?

The author's answer:

Any kind. Normally, you get single-mode operation only when taking special measures, except in some cases with a very short laser resonator and a small gain bandwidth. Inhomogeneous broadening can make it more difficult to reach that goal.

2022-12-12

You mention that 'inhomogeneous broadening is strongly related to inhomogeneous saturation in laser gain media'. Wouldn't that relationship better be described as cause and effect, rather than 'strongly related'?

The author's answer:

No, these are just two phenomena, and we cannot consider one as the cause of the other. Saturation is something occurring at high optical intensities, while the broadening has nothing to with intensities.

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.

Your question or comment:

Spam check:

  (Please enter the sum of thirteen and three in the form of digits!)

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.

preview

Share this with your friends and colleagues, e.g. via social media:

These sharing buttons are implemented in a privacy-friendly way!

Code for Links on Other Websites

If you want to place a link to this article in some other resource (e.g. your website, social media, a discussion forum, Wikipedia), you can get the required code here.

HTML link on this article:

<a href="https://www.rp-photonics.com/inhomogeneous_broadening.html">
Article on Inhomogeneous broadening</a>
in the <a href="https://www.rp-photonics.com/encyclopedia.html">
RP Photonics Encyclopedia</a>

With preview image (see the box just above):

<a href="https://www.rp-photonics.com/inhomogeneous_broadening.html">
<img src="https://www.rp-photonics.com/previews/inhomogeneous_broadening.png"
alt="article" style="width:400px"></a>

For Wikipedia, e.g. in the section "==External links==":

* [https://www.rp-photonics.com/inhomogeneous_broadening.html
article on 'Inhomogeneous broadening' in the RP Photonics Encyclopedia]