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2016
Conference Paper
Titel
Leaky waveguides for low ҡ-measurement: From structure design to loss evaluation
Abstract
For high quality optical coatings the knowledge of the losses of the deposited materials is essential. A precise measurement of low Im(n+iκ)⤠10-6 at an intended operation wavelength and with low intensity can be achieved in waveguide configurations, whereby leaky waveguide configurations allow one to analyze losses of high- and low-index media of H-L-stacks as well due to resonances in the angle-dependent reflection curve. Numerical investigations reveal that different leaky wave schemes, e.g. Bragg-, Bloch- and Antiresonant-Reflecting waveguides, comply differently with practical requests. Loss figure evaluation requires peculiar attention due to measurement accuracy and ambiguities, thus suitable constraints for layer data and a proper merit-function construction have to be used.