Calcium Fluoride Optics

05 May 2023

Calcium fluoride (CaF2) is a crystalline material with excellent transmission from the vacuum ultraviolet (VUV) region through to infrared wavelengths. There are different grades of calcium fluoride each being dependent on the manufacturing process:

• Standard (infrared) grade is made using natural fluorite and therefore the most cost-effective option. However, the natural fluorite can contain impurities which impact its transmission in the UV region.
• UV grade has minimal impurities within the chemically prepared fluorite, and therefore has superior transmission in the UV region. UV grade calcium fluoride is excellent as an Excimer laser optic due to its low absorption, refractive index, and dispersion.
• Raman grade exhibits minimal fluorescence and only has one Raman peak at 321cm­^-1 which is specific to calcium fluoride. With a wide transmission band encompassing VUV to IR, this material is ideal for spectroscopic applications.

Find out more information on our blog where we bring calcium fluoride into the spotlight.

Knight Optical has a range of stock calcium fluoride components including windows, lenses and prisms.

Our stock windows are available in 8mm to 120mm diameters with all options for standard, UV and Raman grade. We also stock 38.5mm x 19mm and 41mm x 23mm drilled cell windows for spectroscopic applications. All our current stock calcium fluoride windows are uncoated, however, if a coating is required, please enquire with our technical sales team.

Calcium fluoride lenses are available as standard and UV grade with focal lengths from 13mm to 467mm, with negative focal length options.

Knight Optical also stock right angle and equilateral calcium fluoride prisms which are ideal for applications utilising UV through to IR wavelengths.

Knight Optical can also provide custom calcium fluoride optical components including windows, lenses and prisms with differing dimensions to our stock components, and  addition of a coating such as an AR coating or beamsplitter and filter coatings dependent on your application.

Our typical capabilities are below: 

Diameter - < 0.25 waves

Form error (@633nm) - < 5mm to 250mm

Centration /parallelism - < 1 arc minute

Scratch/dig - < 60/40

With a metrology laboratory and dedicated QA department, Knight Optical tests all stock and custom optical components against their specification to ensure they meet their requirements. Our equipment includes a Zygo Verifire interferometer for checking surface form error and radii, an Agilent Cary 7000 spectrophotometer for UV and visible transmission/reflections scans, and an Agilent Cary 660 FTIR for infrared transmission measurements.

Contact our UK and US sales team for further information and help with your enquiries.

Europe, UK, Asia & RoW:

Email:  info@knightoptical.co.uk 

Telephone: +44 (0)1622 859444

USA & Canada:

Email:  usasales@knightoptical.com

Telephone: +1 401-583-7846