Chen, WenRoelli, PhilippeHu, HuatianVerlekar, SachinAmirtharaj, Sakthi PriyaBarreda, Angela, IKippenberg, Tobias J.Kovylina, MiroslavnaVerhagen, EwoldMartinez, AlejandroGalland, Christophe2022-01-012022-01-012022-01-012021-12-0310.1126/science.abk3106https://infoscience.epfl.ch/handle/20.500.14299/184229WOS:000728578700059Coherent upconversion of terahertz and mid-infrared signals into visible light opens new horizons for spectroscopy, imaging, and sensing but represents a challenge for conventional nonlinear optics. Here, we used a plasmonic nanocavity hosting a few hundred molecules to demonstrate optomechanical transduction of submicrowatt continuous-wave signals from the mid-infrared (32 terahertz) onto the visible domain at ambient conditions. The incoming field resonantly drives a collective molecular vibration, which imprints a coherent modulation on a visible pump laser and results in upconverted Raman sidebands with subnatural linewidth. Our dual-band nanocavity offers an estimated 13 orders of magnitude enhancement in upconversion efficiency per molecule. Our results demonstrate that molecular cavity optomechanics is a flexible paradigm for frequency conversion leveraging tailorable molecular and plasmonic properties.Multidisciplinary SciencesScience & Technology - Other Topicsenhanced raman-scatteringspectroscopyradiationmicrowavearraystext::journal::journal article::research article