Meta-heuristic approach for the characterization of the constitutive parameters of natural multilayer structures

ALEXANDRE VIAL; MARINA INCHAUSSANDAGUE; DIANA CARINA SKIGIN; DEMETRIO MACÍAS

Bad Honnef

Seminario; 644 Wilhelm und Else Heraeus Seminar: Bio-inspired, Nano- and Microstructured Surfaces: New Functionality by Material and Structure; 2017

644 Wilhelm und Else Heraeus Foundation

Itis well known that a precise knowledge of the constitutive parameters ofnatural structures is required to accurately model their chromatic response andmore   specifically the generation ofstructural colors. In this contribution we show the possibility to retrieve,from spectral reflectance data, the constitutive parameters of a multilayerstructure, as the kind of those found in the exocuticule of some Jewel Beetles.Tosolve the particular inverse problem previously mentioned, we make use ofApproximation Theory and  meta-heuristicoptimization techniques to reformulate it in terms of least-squaresminimization [1,2]. Moreover, we illustrate the versatility of our inversionscheme using two approaches based on different operational principles and weassess their performance through some examples where, to be close to theexperimental situation, we also explore the retrieval of constitutiveparameters from noisy spectra. Furthermore, in order to avoid a somehowarbitrary choice of the  best estimate,we include a post processing statistical stage where we compare the results obtainedwith two central tendency estimators, the mean and the median, and we computetheir associated 95% confidence intervals.References [1]       D, Macias et al., Appl.Opt. 52, 2511 (2013)  [2]       D. Skigin et al., Appl. Opt. 56, 1807 (2017)