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>