Detecting mid-infrared light by molecular frequency upconversion in dual-wavelength nanoantennas

Abstract

<jats:title>Optomechanical upconversion</jats:title> <jats:p> Molecules have rich signatures in their spectra at infrared wavelengths and are typically accessed with dedicated spectroscopic instrumentation. Chen <jats:italic>et al</jats:italic> . and Xomalis <jats:italic>et al</jats:italic> . report optomechanical frequency upconversion from the mid-infrared to the visible domain using molecular vibrations coupled to a plasmonic nanocavity at ambient conditions (see the Perspective by Gordon). Using different nanoantenna designs, one with a nanoparticle-on-resonator and the other with nanoparticle-in-groove, both approaches show the ability to upconvert the mid-infrared vibrations of the molecules in the nanocavity to visible light wavelengths. The effect could be used to simplify infrared spectroscopy, possibly with single-molecule sensitivity. —ISO </jats:p>