Ion beam sputter deposition of optical interference coatings
For now, optical coatings by ion-beam sputtering deposition is the most advanced and high-tech method. The advantages of this method are high adhesion of coatings, ultra-low optical radiation losses due to scattering and absorption.
High energy (from 10 to 20 eV) provides good coating adhesion due to the deposition of material atoms on substrates compared to traditional methods of deposition (electron beam, resistive).
Ultra-low optical radiation losses due to scattering and absorption
Interference coatings formed by ion-beam sputtering have an amorphous structure. The absence of a crystalline phase in the films excludes Rayleigh scattering at the boundaries of crystallites.
Only oxide materials are used to deposit the coatings. Optical coatings have ultra-low optical radiation losses due to the highly optimized deposition technology.
The stability of the process along with use of broadband optical control ensures the high precision of the films deposition with a thickness of less than 10 nm. The thickness non-uniformity of the layers over the entire area of deposition (400 mm in diameter) does not exceed 1%. Due to such precision it meets high performance requirements specified to optical coating specifications.
Stability of the optical parameters
The physical characteristics of oxide films do not change over time because of the high packing density of atoms. They are resistant to the atmospheric exposure, differential temperature and moderate mechanical actions (washing, cleaning). It provides the high stability of the optical coatings characteristics formed by ion-beam sputtering and their long-term operation in optical devices.
The measured optical coating
The catalog of optical coatings includes: anti-reflection coatings (including broadband coatings), ultra-low losses highly reflective mirrors, polarizers (including high radiation resistance polarizers), filters, parametric and beam-splitting coatings.
Due to the accurate calculations of optical characteristics and well-established sputtering technologies we can manufacture products of any complexity according to customer's specifications.
λ = 600…1050 nm, Ra < 0.7%
λ = 780…830 nm, Ta > 99.4%
λ = 1064 nm, Ta = 99.63%
λ = 1380…1450 nm, Ta < 0.05%
Ultra-low loss mirror
λ = 633 nm, α = 44°
Total losses, ppm: Ls < 15 (at RMS = 0.1 nm), Ls < 30 (at RMS = 0.2 nm)
Polarizer with high radiation resistance
λ = 1064 nm, α = 55°, Tp = 99.776%, Ts = 0.075%
Beam strength > 800 MW/cm2 at duration of pulse of 10 ns and S and P- at different polarization angles
λ = 400…480 nm, Ts < 0.05%
λ = 557…587 nm, Ts > 99.1%
λ = 680…806 nm, Ts < 0.06%