wavelengths
 

Metal coatings

Metal coatings have a fair but very broad reflectivity over a certain wavelength range.

LASEROPTIK offers standard mirror coatings such as aluminium, gold or silver, normally with protection layer or even enhanced, i.e. with an additional dielectric coating system.

Reflectivities of metal coatings
Metal coatings have a fair but very broad reflectivity over a certain wavelength range.
Coating types
Metal
HR
  • HR
  • DHR
  • BBHR
  • MHR
  • WHR
  • Metal
Metal
Metal
λ [nm]Al-VUV
R >		Al-VIS-IR
R >		Ag
R >		Au
R >
120 65%      
157 65%      
193 70%      
220 75%      
300 80% 80%    
450   85% 95%  
532   88% 96%  
808   80% 97% 97%
940   87% 97% 97%
1064   92% 97% 97%
1550   92% 97% 98%
2940   92% 97% 97%

Al – Aluminium shows the highest reflectance in the UV. A reflection dip occurs around 850 nm due to phonon absorption. With a fluoride protection layer Al coatings can be optimized for use in the VUV.

Ag – Silver coatings give the highest reflectivity in the VIS and NIR. As they have low GDD in a broad wavelength area they can be taken as simple and low-priced mirrors for femtosecond lasers.

Au – Gold shows poor adhesion to glass and needs a bonding layer of chromium. It is often used in the far IR without a protection layer or as a solderable coating.

Other metal coatings are available too, e.g. chrome, chrome-nickel or platinum.

All values are given for standard coatings. Customized coatings available for all types.

Coating methods available:

EBEIAD

Examples

If not mentioned otherwise, all values and diagrams are given

... for the standard substrate material used in the described wavelength area (mostly Fused Silica or CaF2).

... without consideration of the rear surface.

... with EBE coating technique for a good cost-performance ratio.

Customized coatings are available for all types.

 

–––– dashed lines show the zoomed curve with the stated magnification

Al + Protection Layer – VUV
[B-02250-01]Al + Protection Layer – VUV

120–220 nm: R > 65%

Al + Protection Layer – VIS-IR
[B-00018-01]Al + Protection Layer – VIS-IR

300 nm: R ±3% vs. curve

Ag + Protection Layer
[B-00931]Ag + Protection Layer

450-500 nm: R > 95%; 500-1100 nm: R > 97%

Au + Protection Layer
[B-06039]Au + Protection Layer

IR: R > 97%

Ag enhanced HR 650-1350 nm for fs / 45°
[B-10662-02]Ag enhanced HR 650-1350 nm for fs / 45°

650–1350 nm: Ravg > 98%

Al enhanced 532 nm / 45°
[B-08462]Al enhanced 532 nm / 45°

532 nm: R > 97%

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