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Resonator Design

Definition: the description of the optical components from which an optical resonator is made, and their exact arrangement

German: Resonatordesign

Categories: methods, optical resonators

How to cite the article; suggest additional literature

The term resonator design (or cavity design) is most often used in the context of laser resonators for solid-state bulk lasers. The design of such an optical resonator basically means to define the arrangement of optical elements (e.g. laser mirrors) including their exact distances, so that the resonator modes have the desired properties. The mechanical design can also be an important aspect.

Important Resonator Properties

The design goals for resonators, particularly for laser resonators, can include a large number of aspects which can affect various performance details:

The importance of these criteria should not be underestimated. There are cases where very significant improvements of performance of a laser and also greatly reduced alignment sensitivity can be achieved with an optimized resonator.

Typical Trade-offs in Resonator Design

The optimization of a resonator can involve various trade-offs:

Therefore, successful optimization is possible only on the basis of a solid understanding of the specific requirements, the relevant physical effects, and the trade-offs involved.

The Design Problem

Whereas it is normally not very difficult to evaluate the properties of a given resonator, it can be much more challenging to find a resonator design which satisfies multiple criteria such as those listed above. In many cases, finding a good solution requires

A powerful numerical method for resonator design is to define a “figure of merit”, calculated as the sum of “penalties” for all non-ideal properties, and to minimize that with numerical techniques by varying resonator arm lengths and possibly mirror curvatures. Because the figure of merit often has a huge number of local extrema, a Monte-Carlo method is sometimes used for finding the global optimum or at least a good solution. Note that the procedure starts with some basic resonator structure, which may have to be varied as long as no good solution is found.

Particularly challenging resonator design tasks arise in the context of mode-locked lasers, with combinations of various mode sizes, resonator length constraints, and other complications.


The RP Photonics Buyer's Guide contains 8 suppliers for software and services for resonator design. Among them:


[1]D. Metcalf et al., “Laser resonators containing self-focusing elements”, Appl. Opt. 26 (21), 4508 (1987)
[2]A. E. Siegman, “New developments in laser resonators”, Proc. SPIE 1224, 2 (1990)
[3]V. Magni et al., “Recent developments in laser resonator design”, Opt. Quantum Electron. 23, 1105 (1991)
[4]G. Cerullo et al., “Resonators for Kerr-lens mode-locked femtosecond Ti:sapphire lasers”, Opt. Lett. 19 (11), 807 (1994)
[5]R. Paschotta, “Beam quality deterioration of lasers caused by intracavity beam distortions”, Opt. Express 14 (13), 6069 (2006)
[6]S. Yefet and A. Pe'er, “A review of cavity design for Kerr lens mode-locked solid-state lasers”, Appl. Sci. 3 (4), 694 (2013)
[7]For German readers: R. Paschotta, “Resonatordesign – unterschätztes Potenzial für bessere Laser”, http://www3.interscience.wiley.com/cgi-bin/fulltext/116313857/PDFSTART, Laser Technik Journal 4 (4), p. 50 (2007)
[8]A. E. Siegman, Lasers, University Science Books, Mill Valley, CA (1986)
[9]N. Hodgson and H. Weber, Laser Resonators and Beam Propagation, 2nd edn., Springer, Berlin (2005)

(Suggest additional literature!)

See also: optical resonators, lasers, laser resonators, enhancement cavities, stability zones, alignment sensitivity, laser design, Spotlight article 2011-06-10
and other articles in the categories methods, optical resonators

Dr. R. Paschotta

This encyclopedia is authored by Dr. Rüdiger Paschotta, the founder and executive of RP Photonics Consulting GmbH. Contact this distinguished expert in laser technology, nonlinear optics and fiber optics, and find out how his technical consulting services (e.g. product designs, problem solving, independent evaluations, or staff training) and software could become very valuable for your business!

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