Dark-field spectroscopy of whispering gallery mode cavities

Cylindrical resonators fabricated by direct laser writing and supporting whispering gallery modes are analyzed numerically and experimentally using dark-field spectroscopy. Electric field intensity distribution corresponding to the whispering gallery modes is observed directly in scattered radiation in the visible spectrum range. In the the dark-field spectroscopy experiments, we observed beating of photon density of states, which is explained by the excitation of the eigenmodes of higher radial order. Numerical simulation of both spectrum and mode intensity distribution is provided and good agreement with the experiment is achieved.