A cool route to nanospectroscopy Confining light to a cavity is often used to enhance the interaction between the light and a particle stored within the cavity. Benz et al. worked with a self-assembled monolayer of biphenyl-4-thiol molecules sandwiched between a gold film and a gold nanoparticle. They used laser irradiation to move atoms in the nanoparticle and produced a “picocavity” that was stable at cryogenic temperatures. The authors were then able to obtain time-dependent Raman spectra from individual molecules. Such subwavelength cavities that can localize light to volumes well below 1 nm 3 will enable optical experiments on the atomic scale. Science , this issue p. 726