Patent ID: 7936643

Claim:
A thermally assisted magnetic head, comprising: a plasmon antenna; an optical wave guide having the plasmon antenna installed at the tip thereof, wherein the optical wave guide has a through hole penetrating in the thickness direction thereof, and a core of the optical wave guide has two side faces, a two-dimensional shape of the two side faces forms a part of a parabola; reflection films formed on the side faces, the reflection films being made of Al; a magnetic pole passing through the through hole of the optical wave guide, wherein the magnetic pole comprises a laser beam absorbing or scattering body, the magnetic pole including two or three of Ni, Fe, and Co; a diffraction grating which is disposed in or on the optical wave guide; and a laser element which is disposed at a position to irradiate laser beams onto the diffraction grating, and comprises a photonic crystal surface emitting semiconductor laser, the laser beams propagating toward a recording medium, wherein a two-dimensional shape of the laser beams on the diffraction grating is a ring or two ellipses, wherein a laser light intensity distribution in an area in which the diffraction grating is disposed has at least two intensity peaks in a width direction of the optical wave guide, the width direction is a track width direction of the recording medium, the magnetic pole being arranged on a line, the line extending in a propagating direction of the laser beams from a trough position between the intensity peaks, the photonic crystal surface emitting semiconductor laser comprises: a bottom clad layer comprising a compound semiconductor; a top clad layer comprising a compound semiconductor; an active layer, disposed between the bottom clad layer and the top clad layer; and a photonic crystal layer disposed between the top clad layer and the active layer, the photonic crystal layer has a plurality of through holes penetrating in a thickness direction, and a two-dimensional form of each through hole is a circle, a plan view of the photonic crystal layer is defined by Y-axis and Z-axis, the through holes are aligned in the Y-axis and the Z-axis, an interval Y 1 between the through holes in the Y-axis direction is in a range between 0.1 to 0.8 μm, and an interval Z 1 between the through holes in the Z-axis direction is in a range between 0.1 to 0.8 μm.