Windows
Windows
Our CO2 laser windows are made from Laser Grade ZnSe and coated with low absorbing and low reflectance coatings. Windows from other materials such as Germanium, Silicon, Zinc Sulphide (ZnS) can also be made and coated for other wavelengths.
ZnSe windows can be fabricated in dimensions from 5.0 mm to 300 mm diameter, and in thicknesses from 1.0 mm up to 50 mm (related to diameter and pressure differential). Many standard sizes are manufactured and held in stock. Square and rectangular ZnSe windows can be fabricated to order.



Laser Protection Windows
ULO Optics’ Laser Protection windows are used to protect your system from back spatter, smoke residue and steam, whilst also acting as a pressure window for the cutting gas. Also known as cover slides, debris windows and debris shields, our protective windows are available in various shapes and sizes.
Protection windows are the final optical element, and are placed between the focussing lens and the working area to protect other, more expensive optical elements in your fiber or YAG laser. All our protection windows are AR coated to minimise absorption and prevent damage caused by back reflection or thermal changes to the glass. We offer AR coatings in the wavelength range of 200-3000nm and can offer Narrow-band, Broadband and Multispectral options. We offer windows in a number of substrates, most commonly Fused Silica, BK7, Borosilicate glass 3.3, Float glass and Sapphire.
Key Advantages
Low absorption, high transmission, AR coatings. Several diameters, shapes and sizes available.
Standard laser protection windows
Specifications:
- Substrate: Fused Silica for high power lasers
- Tolerance: ر0.1mm or +0/2.0mm
- Thickness:: ±0.1mm or +0/-0.2mm
- Edges grinded with facette (f.e. 0.3mmx45°)
- Both sides mechanically polished λ/4-λ/6
- Scratch/dig 60/40 or 40/20
- Typical Standard Coatings: @1064nm T≥99.6% & @633nm T≥95% or broad band coating: for example @9001080nm T≥99.5%
- Smudge and scratch-resistant, adhesive peeling tested, ultrasonically cleaned in a dust-free booth.
Common protection windows
Part No | Material | Diameter | ET | Coating |
19.7FSW3-00 | FS | 19.7mm | 3mm | AR/AR |
22.35FSW5-00 | FS | 22.35mm | 4mm | AR/AR |
24FSW4-00 | FS | 24mm | 5mm | AR/AR |
27.9FSW4.1-00 | FS | 27.9mm | 4.1mm | AR/AR |
30FSW1.5-00 | FS | 30mm | 1.5mm | AR/AR |
30FSW5-00 | FS | 30mm | 5mm | AR/AR |
34FSW5-00 | FS | 34mm | 5mm | AR/AR |




Part No | Material | Diameter | ET | Coating |
34FSW5-00 | FS | 34mm | 5mm | AR/AR |
35FSW1.5-00 | FS | 35mm | 1.5mm | AR/AR |
36FSW5-00 | FS | 36mm | 5mm | AR/AR |
37FSW7-00 | FS | 37mm | 7mm | AR/AR |
40FSW7-00 | FS | 40mm | 7mm | AR/AR |
50FSW8-00 | FS | 50mm | 8mm | AR/AR |
55FSW1.5-00 | FS | 55mm | 1.5mm | AR/AR |
Brewster Windows


- Wedged to between 3 and 5 arcminutes in order to overcome multiple interference
- Coated or uncoated versions and many sizes available
- Also available in matched wedge pairs
Part No | Material | Diameter | ET | Coating |
ZBW2510 | ZnSe | 25mm | 3mm | Uncoated ZnSe |
ZBW3315 | ZnSe | 33mm | 3mm | Uncoated ZnSe |
EZBW4015 | ZnSe | 40mm | 3mm | AR/U-EB |
ZBW4218 | ZnSe | 42mm | 3mm | Uncoated ZnSe |
ZBW5018 | ZnSe | 50mm | 3mm | Uncoated ZnSe |
EZBW5018 | ZnSe | 50mm | 3mm | AR/U-EB |
ZBW5320 | ZnSe | 53mm | 3mm | Uncoated ZnSe |
ZBW6122 | ZnSe | 61mm | 3mm | Uncoated ZnSe |
ZBW6323 | ZnSe | 63mm | 3mm | Uncoated ZnSe |
ZBW6625 | ZnSe | 66mm | 3mm | Uncoated ZnSe |
EZBW6625 | ZnSe | 66mm | 3mm | AR/U-EB |
ZBW10038 | ZnSe | 100mm | 3mm | Uncoated ZnSe |
ZBW11542 | ZnSe | 115mm | 3mm | Uncoated ZnSe |
ZBW13248 | ZnSe | 132mm | 3mm | Uncoated ZnSe |
Coatings
ULO Optics is the leading European manufacturer of laser optics, a position held for more than two decades. The optics manufactured by ULO are often used in high power laser systems and have always been designed for such environments. Apart from optimum design and manufacturing standards, the key to the success of any optic relates to the coating performance.
A wide range of coatings are available for our products.
- AR coatings for lenses and windows include standard AR, UltraLO AR, Dual-Band AR, Broad & Wide-Band AR and diamond-like carbon (DLC) AR. The AR coatings can be tailored for your specific wavelengths as needed. And special coating is available for Brewster windows which enhances the difference in S and P reflectance/transmittance.
- Special coatings for 9.3 um and 9-11 um available.
- Mirrors can be Supermax R, NiCu Gold, and Gold coated copper. Phase retarders are available on copper and silicon. We also offer a specialized coating for polarization forcing mirrors.
- Partial reflectors are available from 0.75% to 99.9%, plus a polarization-insensitive 50:50 beam splitter as well as beam combiners.



Ultra-Lo Coatings


UltraLO optics are specifically fabricated for use in the growing family of CO2 high power lasers. The total lens absorption of the UltraLO coating is significantly less than < 0.15% at 10.6 microns. Typically the results from 2014 measured 0.10% on 9mm thick parts.
UltraLO lenses will handle the same high power as conventional lenses but with less optical distortion and a smaller focal length shift due to less heating of the substrate. Additionally, the lower absorption of the UltraLO lenses can lead to longer lens lifetime.
- Lower thermal effects in optics at high power
Supermax R Coatings
Supermax R coated mirrors offer exceptional performance with high reflectivity. The Supermax R coating offers high durability, withstanding the MIL-Spec severe abrasion test making them easily cleaned, leading to longer mirror lifetime. Every Supermax R optic, in addition to its other high performance characteristics, also provides zero phase shift (+/- 2°) at 10.6 microns.
Supermax coated silicon mirrors are the ideal choice for a variety of applications, from beam path fold mirrors to lightweight scanner mirrors. Supermax copper mirrors can also be used for various functions such as fold mirrors, zero phase optics and intracavity mirrors, giving the user outstanding performance without compromise.
- Zero phase retardation
- >99.8% average reflectance
- Rs = 99.93%, Rp = 99.81%
- Absorption at normal incidence = 0.11%.
- ThF4 free