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Proceedings Paper

Light micro-lensing effect in biosilica shells of diatoms microalgae
Author(s): E. De Tommasi; L. De Stefano; I. Rea; L. Moretti; M. De Stefano; I. Rendina
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Paper Abstract

Diatoms are monocellular micro-algae provided with external valves, the frustules, made of amorphous hydrated silica. Frustules present patterns of regular arrays of holes, the areolae, characterized by sub-micrometric dimensions. In particular, frustules from centric diatoms are characterized by a radial disposition of areolae and exhibit several optical properties, such as photoluminescence variations in presence of organic vapors and photonic-crystal-like behaviour as long as propagation of electromagnetic field is concerned. We have studied the transmission of coherent light, at different wavelengths, through single frustules of Coscinodiscus Walesii diatoms, a centric species characterized by a diameter of about 150 μm. The frustules showed the ability to focalize the light in a spot of a few μm2, the focal length depending on the wavelength of the incident radiation. This focusing effect takes place at the centre of the frustule, where no areolae are present and, as it is confirmed by numerical simulations, it is probably due to coherent superposition of unfocused wave fronts coming from the surrounding areolae. Diatoms-based micro-lenses could be used in the production of lensed optical fibers without modifying the glass core and, in general, they could be exploited with success in most of the optical micro-arrays.

Paper Details

Date Published: 14 May 2008
PDF: 5 pages
Proc. SPIE 6992, Micro-Optics 2008, 69920F (14 May 2008); doi: 10.1117/12.781021
Show Author Affiliations
E. De Tommasi, Institute for Microelectronics and Microsystems, CNR (Italy)
L. De Stefano, Institute for Microelectronics and Microsystems, CNR (Italy)
I. Rea, Institute for Microelectronics and Microsystems, CNR (Italy)
Univ. of Naples Federico II (Italy)
L. Moretti, Institute for Microelectronics and Microsystems, CNR (Italy)
Univ. Mediterranea of Reggio Calabria (Italy)
M. De Stefano, Second Univ. of Naples (Italy)
I. Rendina, Institute for Microelectronics and Microsystems, CNR (Italy)

Published in SPIE Proceedings Vol. 6992:
Micro-Optics 2008
Hugo Thienpont; Peter Van Daele; Jürgen Mohr; Mohammad R. Taghizadeh, Editor(s)

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