Nature Photonics 3, 641 - 644 (2009)
Published online: 25 October 2009 | doi:10.1038/nphoton.2009.189
Subject Category: Biophotonics
A biological quarter-wave retarder with excellent achromaticity in the visible wavelength region
N. W. Roberts1,2, T.-H. Chiou3, N. J. Marshall3 & T. W. Cronin4
Abstract
Animals make use of a wealth of optical physics to control and manipulate light, for example, in creating reflective animal colouration1, 2, 3 and polarized light signals4. Their precise optics often surpass equivalent man-made optical devices in both sophistication and efficiency5. Here, we report a biophysical mechanism that creates a natural full-visible-range achromatic quarter-wave retarder in the eye of a stomatopod crustacean. Analogous, man-made retardation devices are important optical components, used in both scientific research and commercial applications for controlling polarized light. Typical synthetic retarders are not achromatic, and more elaborate designs, such as, multilayer subwavelength gratings or bicrystalline constructions, only achieve partial wavelength independence6. In this work, we use both experimental measurements and theoretical modelling of the photoreceptor structure to illustrate how a novel interplay of intrinsic and form birefringence results in a natural achromatic optic that significantly outperforms current man-made optical devices.
Photon Science Institute, School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK
School of Biological Sciences, University of Bristol, Woodland Road, Bristol BS8 1UG, UK
Sensory Neurobiology Group, School of Biomedical Sciences and Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
Department of Biological Sciences, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, Maryland 21250, USA
Correspondence to: N. W. Roberts1,2 e-mail: nicholas.roberts@bristol.ac.uk
+++++
+++++
NOTA DESTE BLOGGER:
Pobre Darwin, ele era totalmente ignorante desta complexidade visual, mas muito honesto em dizer que só em pensar neste sistema lhe dava calafrios. Mesmo assim, especulou a transmutação das espécies, algo muito mais complexo do que um simples olho...
