Fabrication of a Dual-Tier Thin Film Micro Polarization Array
Postprint version. This paper was published in Optics Express, Volume 15, Issue 8, April 2007, pages 4994-5007 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/abstract.cfm?URI=oe-15-8-4994. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law.
A thin film polarization filter has been patterned and etched using reactive ion etching (RIE) in order to create 8 by 8 microns square periodic structures. The micropolarization filters retain the original extinction ratios of the unpatterned thin film. The measured extinction ratios on the micropolarization filters are ~1000 in the blue and green visible spectrum and ~100 in the red spectrum. Various gas combinations for RIE have been explored in order to determine the right concentration mix of CF4 and O2 that gives optimum etching rate, in terms of speed and under-etching. Theoretical explanation for the optimum etching rate has also been presented. In addition, anisotropic etching with 1μm under cutting of a 10μm thick film has been achieved. Experimental results for the patterned structures under polarized light are presented. The array of micropolarizers will be deposited on top of a custom made CMOS imaging sensor in order to compute the first three Stokes parameters in real time.
Viktor Gruev, Alessandro Ortu, Nathan Lazarus, Jan Van der Spiegel, and Nader Engheta. "Fabrication of a Dual-Tier Thin Film Micro Polarization Array" Departmental Papers (ESE) (2007).
Available at: http://works.bepress.com/jan_vanderspiegel/7