Multimode interferometers are coming of age both as sensors and components of quantum circuits.Here we investigate an interferometer based on a porous thinfilm sensor of refractive index of fluids. Eigenmode analysis is used to identify effective single- and multi-mode sensing regimes and the corresponding realizations of interferometer. A general measure in a form of Fisher information is introduced to describe the impact of the film porosity on sensitivity and nonlinearity of the interferometer. As high sensitivity relies on formation of a highly peaked mode in the film, a parallel with plasmonic sensors is drawn. Close correlations between the sensor nonlinearity, mode profile and the shape of Fisher information function indicate the potential of this measure in describing complex non-Gaussian multimode structures
School of Electrical Engineering, University of Belgrade, BulevarKralja Aleksandra 73, 11120 Belgrade, Serbia, and P* Group, Vinča Institute of Nuclear Sciences, University of Belgrade, P.O.B. 522, Belgrade, Serbia
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Financed by the National Centre for Research and Development under grant No. SP/I/1/77065/10 by the strategic scientific research and experimental development program:
SYNAT - “Interdisciplinary System for Interactive Scientific and Scientific-Technical Information”.