Solar-blind Coating

Download Coating Datasheet (PDF, 264 KB)

As a fusion of last R&D works Tydex offers complicated coating which allows to transmitt effectively infrared radiation over very wide range and simultaneously to eliminate solar shortwave emission. It is so called solar-blind coating. The cut-off wavelength is controlled with high accuracy.

Tydex offers this coating deposited on Si substrates. Special grade of the used silicon allows to minimize absorption at working wavelength range.

Depending on the application we introduce items with one-side solar-blind coating (fig. 1) as well as with DLC applied ouside (fig. 2).

 Solar-blind Coating


Coating sandwich
Wavelength range
6-15 µm
Wavelength range
18-40 µm
DLC+Si substrate +solar blind T average>=70%
T peak=85-90%
T min=60%
T average>=50%
T peak=55-60%
T min=35-40%
Si substrate +solar blind
(without DLC)
T average>=55%
T peak=60-70%
T min=50%
T average>=45%
T peak=50-55%
T min=35-40%
Additional specification to both coating sandwiches
Working temperature range
-40 deg. C ...+80 deg. C
relatively high, up to 90-95%
Cut-off wavelength
(to be specified additionally)
4.5 +/- 0.3 µm
T peak (not more than 2 peaks)
at the range before cut-off
<=0.4% (in the range 1-4.5µm)
The range where transmission
exceeds 20%
up to 45 µm


Similar solar-blind coatings are widely used in pyrgeometers (devices for measuring an effective atmospheric infrared radiation spectrum that extends approximately from 4.5um to 100um).
Tydex optics with solar-blind coating were suscesfully tested and certified in the Physical-Meteorological Observatory at Davos (Switzerland).