Magnetron sputtering of precision optical coatings enabled by process stability of rotatable cathodes

Cylindrical rotatable cathodes deliver huge material amounts under stable conditions as needed for interference coatings. Sub-stoichiometric targets and plasma oxidation produce low absorbance and virtually no drift of refractive index associated with changeless material uniformity

Recent developments in precision optical coatings prepared by cylindrical magnetron sputtering

Cylindrical targets give the opportunity to improve the process stability of magnetron sputtering processes although reactive deposition might be a challenge. Sputtering from metal doped oxide targets in connection with a plasma source unlocks the full potential: the process can be driven in well-known mid-frequency mode and the plasma source ensures fully stoichiometric films with low loss. During the last years different developments for oxide cylindrical targets were done. The suitable composition has to be found regarding e.g. the density and an arc-free process as familiar for planar targets. In the tube geometry new manufacturing methods are required that ensure these properties. In the present paper we show some examples of the high refractive index materials tantalum oxide: single film characterization as well as realized complex precision optical filters. The results are accompanied by performance measurements in terms of uniformity over 200 mm glass wavers as well as carrier to carrier and batch to batch. These were measured by the position of a quarter-wave stack's edge

Deposition of abrasion resistant single films and antireflective coatings on sapphire

A series of different oxide and nitride antireflective coatings as well as single films on sapphire substrates have been deposited by magnetron sputtering. The layer stacks consist of 5–7 individual layers with a total thickness of around 300nm. Both high-index materials and low-index material were analyzed. The mechanical stability was investigated by means of optical haze increase during falling sand (“sand trickling test”) and by thickness loss during oscillating abrasionin a sand bath (tightened “Bayer test”). The dependence of the abrasion tests results on mechanical film properties, i.e. the nanoindentor hardness, was analyzed. No clear correlation of the Bayertest results and the sand trickling test results was found, which indicates that the abrasion mechanisms are different. A nitride basedantireflective coating with excellent properties from both tests has been produced

Modeling of Cellular Systems: Application in Stem Cell Research and Computational Disease Modeling

The large-scale development of high-throughput sequencing technologies has allowed the generation of reliable omics data at different regulatory levels. Integrative computational models enable the disentangling of a complex interplay between these interconnected levels of regulation by interpreting these large quantities of biomedical information in a systematic way. In the context of human diseases, network modeling of complex gene-gene interactions has been successfully used for understanding disease-related dysregulations and for predicting novel drug targets to revert the diseased phenotype. Furthermore, these computational network models have emerged as a promising tool to dissect the mechanisms of developmental processes such as cellular differentiation, transdifferentiation, and reprogramming. In this chapter, we provide an overview of recent advances in the field of computational modeling of cellular systems and known limitations. A particular attention is paid to highlight the impact of computational modeling on our understanding of stem cell biology and the complex multifactorial nature of human diseases and their treatment