Encyclopedia … combined with a great Buyer's Guide!

With Wavelength Combs to Picometer Resolution

Posted on 2006-07-01 as part of the Photonics Spotlight (available as e-mail newsletter!)

Permanent link: https://www.rp-photonics.com/spotlight_2006_07_01.html

Author: Dr. Rüdiger Paschotta, RP Photonics AG, RP Photonics AG

Abstract: An interesting new technique makes it possible to measure displacements with a resolution of picometers.

Dr. Rüdiger Paschotta

Ref.: T. R. Schibli, K. Minoshima, Y. Bitou, F.-L. Hong, H. Inaba, A. Onae, and H. Matsumoto, "Displacement metrology with sub-pm resolution in air based on a fs-comb wavelength synthesizer", Opt. Express 14 (13), 5984 (2006)

Optical frequency combs as generated from carefully stabilized mode-locked laser sources represent equidistant set of very well defined optical frequencies. However, the corresponding wavelengths in air are much less well defined, as the refractive index of air undergoes changes due to varying pressure and humidity. As wavelength stability rather than frequency stability is the actually required feature for some displacement measurement schemes (e.g. based on Fabry–Perot interferometers), researchers have turned a frequency comb into a wavelength comb, where all spectral components have a quite precisely constant wavelength in air. This allowed them to make extremely precise displacement measurements without using an air-tight enclosure of their setup. For example, they can monitor extremely tiny drifts of a cavity length on the scale of some tens of picometers, or to measure the tiny nonlinear error of an ultraprecise nanopositioning translation stage of just a few a picometers over a translation range of 12 μm.

It is apparent that frequency combs from mode-locked lasers generate a wide range of opportunities in metrology – not only in frequency metrology, but also in other fields. Companies in the field of laser metrology are well advised to take notice of these developments.

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 RP Photonics Encyclopedia.

Note that you can also receive the articles in the form of a newsletter or with an RSS feed.

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. (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.

Spam check:

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.


Share this with your network:

Follow our specific LinkedIn pages for more insights and updates:

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/spotlight_2006_07_01.html">
Article on With Wavelength Combs to Picometer Resolution</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/spotlight_2006_07_01.html">
<img src="https://www.rp-photonics.com/previews/spotlight_2006_07_01.png"
alt="article" style="width:400px"></a>