Enhanced transmission with tunable Fano-like profile in magnetic nanofluids

Abstract

We observe a Fano-like resonance in a magnetically polarizable nanofluid. Under an external magnetic field, the transmittance spectrum of a ferrofluid emulsion containing droplet size of ~220 nm shows an enhanced peak with a Fano-like profile, which is attributed to a localized waveguide resonance from random array of tubes with charged inner surface that are formed by the alignment of the droplets. Furthermore, by varying the magnetic field, the Fano profile is tuned and an opaque emulsion is turned into a transparent one. This finding may have interesting applications in tunable photonic devices.