COATINGS

Filter

Optical filters are used when various wavelength ranges need to be transmitted and others reflected.

Opcos has established a variety of processes for various filter coatings, the names of which are derived from the respective application:

SWP – Shortwave pass filter

  • shortwave radiation is (λ < λ0) transmitted
  • longwave radiation is (λ > λ0) reflected
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LWP – Longwave pass filter

  • shortwave radiation (λ < λ0) is reflected
  • longwave radiation (λ > λ0) is transmitted

BP – Bandpassfilter

  • shortwave radiation (λ < λ0) is reflected
  • medium-wave radiation (λ0 < λ < λ1) is transmitted
  • longwave radiation (λ > λ1) is reflected
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NTC - Notch filters

  • shortwave radiation (λ < λ0) is transmitted
  • medium-wave radiation (λ0 < λ < λ1) is reflected
  • longwave radiation (λ > λ1) is transmitted

ARB - Arbitrary

Filter coatings often require combinations of the listed filter types and are highly application-specific in terms of wavelength range, angle of incidence range, and polarization direction. Therefore, filter coatings are usually tailored to the respective products.

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