Experimental method for reliably establishing the refractive index of buprestid beetle exocuticle
Noyes, Joseph Alexander
Hooper, Ian R.
University of Exeter
Optical Society of America
In this study we apply an existing optical characterisation technique to establish reliably the complex refractive indices of layers comprising a natural multilayer reflector in the beetle Chrysochroa raja. Its reflector characteristics, ultrastructure and layer thicknesses were established using electron and optical microscopy. We recorded a significant number of wavelength dependent optical data sets from the same regions of sample using both linear polarisations and from a variety of different angles. These optical data sets were modelled simultaneously in order to significantly reduce the degeneracy of the fitting process. For the C. raja sample in question, the fitted complex refractive indices of both layer types were determined to be n=1.68 k=0.03 and n=1.55 k=0.14.
Copyright © 2007 Optical Society of America. This paper was published in Optics Express and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-15-7-4351 . Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law.
15 (7), pp. 4351-4358