Titelbild: Room-Temperature Single-Molecule Infrared Imaging and Spectroscopy through Bond-Selective Fluorescence (Angew. Chem. 52/2024)

Chemical bonds in dye molecules are vibrationally excited by a narrowband mid-IR pulse and upconverted by a synchronized near-IR pulse. Doubly excited molecules emit fluorescence encoding mid-IR information. This bond-selective fluorescence-detected IR-excited (BonFIRE) method allows wide-field single-molecule mid-IR imaging and spectral profiling at room temperature, for robust characterization of polarization, peak position, linewidth, and vibrational relaxation, as reported by Lu Wei et al. in their Research Article (e202413647).