We report on the realization of a solid state Fabry-Pérot-like microcavity that uses a small Gaussian-shaped deformation inside the cavity to achieve strong lateral photon confinement on the order of the wavelength. Cavities with a mode volume V < 0.4 μm3 and a quality factor Q > 1000 are fabricated by means of focused ion beam milling, removing the necessity for etched sidewalls as required for micropillar cavities. Perylene-diimide dye doped polystyrene was embedded in the microcavity and probed by time-resolved microphotoluminescence. A Purcell enhancement of the spontaneous emission rate by a factor of 3.5 has been observed at room temperature. © 2013 AIP Publishing LLC.