Development of a hybrid monitoring strategy to the deposition of chirped mirrors by plasma-ion assisted electron evaporation

Abstract

We report on a hybrid monitoring strategy, which makes use of quartz crystal monitoring and broadband optical monitoring data in application to the deposition of chirped mirrors for the near infrared spectral region. We present a short description of the basic monitoring concept, the experimental setup, and the data elaboration facilities of the developed optical monitoring system OptiMon. Although being flexible enough to be implemented into different types of deposition system, we focus here on the application of our monitoring system for coating preparation with Advanced Plasma Source (APS) assisted electron beam evaporation. Chirped mirrors have been prepared using SiO2 and Ta2O5 as low and high index materials, respectively. The layers are characterized by in-situ transmission spectroscopy, ex-situ transmission and reflection spectroscopy, and white light interferometry to determine the group delay dispersion GDD. Basing on characterization results, we demonstrate and discuss the relative benefits of the developed monitoring strategy

Online Characterization Algorithms for Optical Coating Production with Broadband Monitoring

“…In the following, we refer to these algorithms as online monitoring algorithms. The new hybrid algorithms combining information from the optical and non-optical sensors allow one to achieve a better accuracy of layer thickness control [17][18][19]. However, along with these developments, it is also extremely important to provide online monitoring algorithms with the best possible estimation of the thicknesses of all previously deposited layers.…”