The media heating device of the magnetic head includes an optical resonant cavity produces a high intensity near-field optical beam of subwavelength dimension adjacent to the write pole. A suitable resonant cavity may be a spherical cavity, disk shaped cavity, ring shaped cavity, racetrack shaped cavity, micropillar cavity, photonic crystal cavity and Fabry-Perot cavity. The cavity is fabricated as a planar thin film structure in layers that are generally parallel to the magnetic pole thin film layers of the magnetic head, such that the principal axis of the resonant cavity is parallel to the air bearing surface (ABS). Optical energy is coupled into the resonant cavity through a waveguide that is placed proximate the cavity, and optical energy is coupled out of the cavity through an aperture that is placed within the cavity. A preferred embodiment may include a nano-aperture disposed between the resonant cavity and the ABS.