| Apr 23, 2026 | New paper out! Have you ever wondered how a laser-pointer works if you shrink it down to nanometer scales? No worries, we’ve got you covered. The smallest lasers consist of a nanometer-sized cavity, made from nanoparticles, with only a handful of molecules in between that serve as gain medium. Together with Kai and Kimmo, we applied our novel BBGKY-HEOM approach (informed from first principles) and discovered something unexpected: the vibrational properties of these molecules can cause unusual resonances in the laser output. These resonances depend on how strongly the molecules are pumped, their vibrational structure, and the number of molecules. The relative strength of resonant features in the lasing output increases with the number of molecules and can not be explained within the mean-field approximation – a feature that might be useful to identify the precise number of participating molecules. Once again, we find that making things smaller certainly doesn’t make it simpler. (Müller et al., 2026) |