Encyclopedia … combined with a great Buyer's Guide!

Sponsoring this encyclopedia:     and others

Ultraviolet Optics

Acronym: UV optics

Definition: optical elements for use with ultraviolet light

More general term: optics

German: Ultraviolett-Optik

Category: general optics

How to cite the article; suggest additional literature


Ultraviolet light behaves in many ways just as visible light, and it can thus in principle be used with the same times of optical elements as visible or near-infrared light: focusing and imaging lenses, mirrors, optical windows, beam splitters, prisms, polarizers, waveplates, optical filters etc. UV mirrors and lenses are also available in aspheric versions, and anti-reflection coatings are available. However, there are certain special aspects to be observed for applications in the UV region:

Examples for UV-transparent Media

UV optics are often made from highly purified calcium fluoride (CaF2), which has a very low UV absorption, high homogeneity, low birefringence, relatively high hardness (compared with other fluoride materials), high physical stability, and high optical damage threshold. It can be used down to ≈ 160 nm and is thus suitable for use, e.g., with argon fluoride (ArF) excimer lasers. However, it is brittle, naturally anisotropic, and hygroscopic. Similar properties are obtained for other purified fluorides such as magnesium fluoride (MgF2) and lithium fluoride (LiF); the latter can be used down to 110 nm. In addition to good UV transparency, such fluorides also offer good infrared properties up to wavelengths of 5 μm and beyond.

As an alternative, UV-grade fused silica can be used even for wavelengths down to ≈ 200 nm, whereas the cheaper standard-grade fused silica has significant attenuation already below 260 nm.

Similar constraints apply to materials chosen for making dielectric coatings, for example in the form of anti-reflection coatings. A frequently used AR coating material is magnesium fluoride (MgF2). Often, manufacturers offer UV anti-reflection coatings without revealing what material(s) they are made of.

Another possible material choice is artificial diamond, which is transparent down to ≈ 230 nm and very robust, but expensive.

For nonlinear frequency conversion, one often uses borate crystals such as LBO and BBO, which exhibit relatively good UV transparency and high resistance.

Some optical fibers can be used in the near-ultraviolet spectral region, although with relatively high propagation losses. Fiber delivery of ultraviolet light is usually not feasible for shorter wavelengths and/or high optical powers.

Common UV Wavelengths

In laser technology, a few ultraviolet wavelengths are particularly common:

Therefore, certain optical elements like lenses and mirrors are specifically developed for such wavelengths and may then be sold as excimer optics, for example.

EUV Optics: Essentially Limited to Reflective Optics

In the EUV region, basically all solid materials are relatively strongly absorbing, and even air causes strong attenuation below ≈ 200 nm, so that e.g. lithography with vacuum UV or EUV light below 100 nm has to be performed in vacuum. Bragg mirrors can still be made for the EUV region, e.g. with molybdenum/silicon (Mo/Si) structures, which allow, e.g., ≈ 70% reflectivity at 12 nm wavelength to be reached. Due to this limited reflectivity, EUV optics have to be designed with the smallest possible number of reflecting surfaces.


The RP Photonics Buyer's Guide contains 61 suppliers for ultraviolet optics. Among them:

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.

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.

See also: ultraviolet lasers, optical materials, optical crystals, scattering
and other articles in the category general optics


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!