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Proceedings Paper

Random rough surface photofabrication
Author(s): Vincent Brissonneau; Ludovic Escoubas; François Flory; Gérard Berginc
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Paper Abstract

Random rough surfaces are of primary interest for their optical properties: reducing reflection at the interface or obtaining specific scattering diagram for example. Thus controlling surface statistics during the fabrication process paves the way to original and specific behaviors of reflected optical waves. We detail an experimental method allowing the fabrication of random rough surfaces showing tuned statistical properties. A two-step photoresist exposure process was developed. In order to initiate photoresist polymerization, an energy threshold needs to be reached by light exposure. This energy is brought by a uniform exposure equipment comprising UV-LEDs. This pre-exposure is studied by varying parameters such as optical power and exposure time. The second step consists in an exposure based on the Gray method.1 The speckle pattern of an enlarged scattered laser beam is used to insolate the photoresist. A specific photofabrication bench using an argon ion laser was implemented. Parameters such as exposure time and distances between optical components are discussed. Then, we describe how we modify the speckle-based exposure bench to include a spatial light modulator (SLM). The SLM used is a micromirror matrix known as Digital Micromirror Device (DMD) which allows spatial modulation by displaying binary images. Thus, the spatial beam shape can be tuned and so the speckle pattern on the photoresist is modified. As the photoresist photofabricated surface is correlated to the speckle pattern used to insolate, the roughness parameters can be adjusted.

Paper Details

Date Published: 1 October 2011
PDF: 9 pages
Proc. SPIE 8172, Optical Complex Systems: OCS11, 81720H (1 October 2011); doi: 10.1117/12.896217
Show Author Affiliations
Vincent Brissonneau, Thales Optronique S.A. (France)
Institut Matériaux Microélectronique Nanosciences de Provence, CNRS, Aix Marseille Univ. (France)
Ludovic Escoubas, Institut Matériaux Microélectronique Nanosciences de Provence, CNRS, Aix Marseille Univ. (France)
François Flory, Institut Matériaux Microélectronique Nanosciences de Provence, CNRS, Ecole Centrale Marseille (France)
Gérard Berginc, Thales Optronique S.A. (France)


Published in SPIE Proceedings Vol. 8172:
Optical Complex Systems: OCS11
Gérard Berginc, Editor(s)

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