  Whispering gallery mode microdisk cavities fabricated by direct laser writing
are studied using dark-field imaging and spectroscopy in the visible spectral
range. {Dark-field imaging allows us to directly visualize the spatial
intensity distribution of whispering gallery modes. We extract their azimuthal
and radial mode indices from dark-field images, and find the axial mode number
from the dispersion relation. The scattering spectrum obtained in the confocal
arrangement provides information on the density of optical states in the
resonator. The proposed technique is a simple non-invasive way to characterize
the optical properties of microdisk cavities.
