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Spectralon Reflectance Material

Labsphere's Spectralon Diffuse Reflectance Material

The highest diffuse reflectance of any material in the 250-2500nm band

Labsphere's Spectralon is a solid thermoplastic that exhibits the highest diffuse reflectance of any material or coating in the 250-2500nm band. Spectralon is used in integrating spheres, laser cavity pumping chambers, reflectance standards and targets, lamp reflectors, display backpanel lighting and digital imaging devices, in fact anywhere where you need efficient, uniform illumination. Spectralon is easily machined into bespoke reflectors.

An Award-Winning Material

Spectralon is Labsphere's patented and award-winning diffuse reflectance material. It is a solid thermoplastic based upon PTFE and exhibits the highest diffuse reflectance of any material or coating, up to 95% from 250-2500nm, and 99% from 400-1500nm. Spectralon is manufactured in optical, laser and space grades and is widely used in applications as diverse as integrating spheres, laser cavity pumping chambers, reflectance targets, lamp reflectors, display backpanels, line scanners and digital imaging devices. A wide variery of optical reference materials are made from Spectralon, including standards of reflectance and BRDF (scatter). Spectralon can be doped with various materials to create standards of grey scale reflectance, fluorescence, wavelength and colour.

Spectralon is not a coating, rather it is a solid material that is machined into reflectors. It is a bulk rather than a surface reflector, with the highest reflectance achieved at thicknesses of ≥7mm. In thinner section, the reflectance of Spectralon decreases (for example, dropping from 99.0% to 93.3% at 1mm thickness @ 555nm). For further information on the relationship between thickness and reflectance, download our Materials TechGuide from the Knowledge Base above.

Unlike most other diffuse reflectance coatings for the UV-VIS-NIR band, Spectralon exhibits an extreme environmental stability. It is hydrophobic,  thermally stable to 350°C, UV-resistant* and chemically inert to all but the most powerful bases such as sodium amide and organo-sodium or lithium compounds. The material is durable and maintains its reflectance even under harsh laboratory or field conditions. Spectralon can be easily cleaned by washing; for badly soiled reflectors, light sanding can restore the original reflectance.

* A useful reference is the NPL paper entitled "Ageing of Materials Under Intense UV Radiation" by Gibbs, D R, Duncan, F J, Lambe, R P, Goodman, T M published in Metrologia, 1996, 32, (6), 601-607. Click here for a link to the publications area on the NPL web site.

Optical Grade Spectralon, SRM-99O

Optical grade Spectralon forms the basis of our integrating spheres as well as our diffuse reflectance standards and targets. Optical grade material can be machined into integrating spheres with diameters up to 300mm, while larger spheres can be made using tiles of Spectralon. Products made using Spectralon deliver marked performance gains compared with ordinary diffuse reflectance coatings. Spectralon is non-wavelength selective, with a variation in reflectance of just 0.5% between 360 and 740nm. Please note that Spectralon is not suitable for use at wavelengths longer than 2.5µm due to strong absorption at 2.8µm and between 5.4 and 8µm.

Laser Grade Spectralon, SRM-99L

Laser grade Spectralon is the perfect choice of material for use as a pump chamber reflector in diode and lamp pumped solid state lasers and lamp pumped dye lasers. Spectralon exhibits diffuse, high reflectance at the pump wavelengths of these lasers leading to increased slope efficiencies, higher energies, increased gain uniformity, improved beam quality and reduced risk of parasitic oscillations. Spectralon is thermally stable, hydrophobic and easily machined into bespoke reflectors. Click here to jump to the Spectralon Laser Reflector page.

Space Grade Spectralon, SRM-99S

Space grade Spectralon has gained widespread acceptance as a reflectance target material used on satellites for earth-observing remote sensing applications. This form of Spectralon is characterised by an extremely high cleanliness and low levels of outgassing whilst retaining Lambertian high reflectance. The material is procesed in a clean-room environment and packaged to protect against molecular and particulate contamination. Space grade Spectralon has undergone extensive testing for VUV exposure, proton bombardment, atomic oxygen exposure, alpha-Lyman radiation, outgassing and static charge testing by national laboratories, such as Jet Propulsion Laboratory, NASA Goddard Space Flight Center, TRW and CSEM. This testing has led to the development of a stringent manufacturing process that eliminates potential contaminants which lead to UV degradation.

Specifications & Ordering Information

Spectralon is not supplied as a bulk material. Instead, reflectors are machined according to a customer-supplied drawing. Our dedicated Spectralon machine shop and expert machinists familiar with the nuances of working with this material ensure that your reflectors are of the highest quality and performance. We operate a fast-track process to help us to respond quickly to one-off or prototype projects. We are just as happy supplying one or one hundred reflectors - there is no minimum order quantity.

» Click here to submit an enquiry for a machined Spectralon reflector

Main Specifications

Spectralon Reflectance Material, SRM-99O

Wavelength Range

250 ... 2500nm


> 95%, 250 ... 2500nm


> 99%, 400 ... 1500nm

Machining Tolerance

up to 100mm: ± 0.13mm

Thermal Stability

to 350°C (decomposes at > 400°C)


1.25 ... 1.5 g/cm3

Water Permeability

< 0.001% (hydrophobic)

Coefficient of Linear Expansion

5.5 ... 6.5E-04 in/in-°C

Vacuum Stability

No outgassing except for entrained air


Non flammible (UL Rating V-0)

Chemical Stability

Inert (incompatible with non-polar solvents & greases)

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