Broadband antireflection coatings with low polarization splitting.

A major problem for optical systems is the polarization splitting occurring at any interface in the event of oblique light. Low-index nanostructured silica layers were produced by overcoating an initial organic structure with silica and subsequent removal of the organic constituents. The nanostructured layers can be tailored to achieve defined low effective refractive indices down to 1.05. They can also be stacked together with homogeneous layers to produce broadband antireflective coatings with very low polarization splitting. Especially thin interlayers that separate the low-index structured layers turned out to be useful to optimize the polarization properties.

Combined antifogging and antireflective double nanostructured coatings for LiDAR applications.

To increase the performance of optical systems, a good antireflective coating is required to ensure low reflectance and high transmittance of optical surfaces. Further problems, such as fogging that causes light scattering, negatively affect the image quality. This implies that other functional properties are also required. Presented here is a highly promising combination of an antireflective double nanostructure on top of an antifog coating with long-term stable properties, generated in a commercial plasma-ion-assisted coating chamber. It is demonstrated that the nanostructures do not affect the antifog properties and can be successfully used for many applications.

Coating-relevant properties of high-index optical polymers for automotive applications.

High-transparent polymers exhibiting a refractive index beyond 1.6 enhance the available range of optical plastics. The aim of this study is to evaluate optical polyesters (OKP-1 and OKP-4) and special new polycarbonates (PCs) (EP-6000 and EP-8000) in comparison with the widely used poly-bisphenol-A-based PC. The work is focused on optical properties as well as other properties that are important for the deposition of optical coatings. Plasma ion-assisted deposition is used for the deposition of an abrasion resistant antireflective coating (AR-hard).

Ultraviolet-transparent low-index layers for antireflective coatings.

Nanostructured low-index layers are useful as the last layers of antireflective (AR) coatings because they can broaden their spectral ranges and improve the performance for oblique light incidence. Structuring of evaporated organic layers by plasma opens a route to produce inorganic interference stacks and low-index layers in the same vacuum process. The organic material uracil has been investigated as a template material for AR nanostructures. An additional plasma-treatment step was added to the manufacturing process, which decreases the organic fraction of the coating substantially. As a result, a better environmental stability and higher transmission in the ultraviolet range was achieved.