10 November 2017 Vapor and liquid optical monitoring with sculptured Bragg microcavities
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J. of Nanophotonics, 11(4), 046009 (2017). doi:10.1117/1.JNP.11.046009
Sculptured porous Bragg microcavities (BMs) formed by the successive stacking of columnar SiO 2 and TiO 2 thin films with a zig-zag columnar microstructure are prepared by glancing angle deposition. These BMs act as wavelength-dependent optical retarders. This optical behavior is attributed to a self-structuration of the stacked layers involving the lateral association of nanocolumns in the direction perpendicular to the main flux of particles during the multilayer film growth, as observed by focused ion beam scanning electron microscopy. The retardance of these optically active BMs can be modulated by dynamic infiltration of their open porosity with vapors, liquids, or solutions with different refractive indices. The tunable birefringence of these nanostructured photonic systems has been successfully simulated with a simple model that assumes that each layer within the BMs stack has uniaxial birefringence. The sculptured BMs have been incorporated as microfluidic chips for optical transduction for label-free vapor and liquid sensing. Several examples of the detection performance of these chips, working either in reflection or transmission configuration, for the optical monitoring of vapor and liquids of different refractive indices and aqueous solutions of glucose flowing through the microfluidic chips are described.
© 2017 Society of Photo-Optical Instrumentation Engineers (SPIE)
Manuel Oliva-Ramirez, Jorge Gil-Rostra, Maria Carmen López-Santos, Agustín R. González-Elipe, Francisco Yubero, "Vapor and liquid optical monitoring with sculptured Bragg microcavities," Journal of Nanophotonics 11(4), 046009 (10 November 2017). https://doi.org/10.1117/1.JNP.11.046009 Submission: Received 12 July 2017; Accepted 23 October 2017
Submission: Received 12 July 2017; Accepted 23 October 2017

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