We measure experimentally the spatial intensity profiles and resonant frequencies of the transverse modes of nearly hemispherical microcavities for a range of cavity lengths and mirror curvatures. The experimental mode profiles are radially symmetric Gauss-Laguerre modes, but do not posses the radial frequency degeneracies typical of Gauss-Laguerre modes in large-scale optical cavities. We use a paraxial model of cavity propagation to interpret the experimental results. In particular, we show that the lifting of the radial frequency degeneracy may be due to the strength of spherical aberration in wavelength-scale microcavities.

• Received 10 July 2008

DOI:https://doi.org/10.1103/PhysRevA.79.043822