Optical modes in oxide-apertured micropillar cavities
  We present a detailed experimental characterization of the spectral and spatial structure of the confined optical modes for oxide-apertured micropillar cavities, showing good-quality Hermite-Gaussian profiles, easily mode-matched to external fields. We further derive a relation between the frequency splitting of the transverse modes and the expected Purcell factor. Finally, we describe a technique to retrieve the profile of the confining refractive index distribution from the spatial profiles of the modes. 
Cristian Bonato, Jan Gudat, Keesjan de Vries, Hyochul Kim, Susanna M.   Thon, Pierre M. Petroff, Martin P. van Exter and Dir...
cond-mat.mes-hall physics.optics quant-ph