Heat-assisted magnetic recording device having external cavity laser with slot waveguide

A method comprising:

• applying current to an active laser region with a reflective back facet and a front facet externally coupled to an input surface of a slider, the application of the current causing energy to be emitted into the input surface;
• receiving the energy from the input surface at a slot waveguide comprising first and second high-index regions surrounding a middle region that extends along a light propagation direction, the middle region having a refractive index less than that of the first and second high index regions, the energy being coupled into the middle region;
• directing the energy from an output portion of the middle region to a near-field transducer at a media-facing surface, the near-field transducer comprising first and second plates parallel to the media-facing surface with a gap therebetween;
• and
• reflecting the energy from the near-field transducer to the reflective back facet such that the reflective back facet and the near-field transducer define a single resonator.

A slider comprising:

• a magnetic write pole near a media-facing surface;
• and
• an external cavity resonator comprising:
• an active laser region with a reflective back facet and a front facet, the front facet optically coupled to an input surface of the slider;
• a slot waveguide configured to receive energy from the input surface, the slot waveguide comprising first and second tapered high-index regions surrounding a tapered middle region that extends along a light propagation direction, the middle region having a refractive index less than that of the first and second high index regions;
• and
• a near-field transducer at an output portion of the middle region near the write pole, the near-field transducer comprising first and second plates parallel to the media-facing surface with a gap therebetween, wherein the energy reflects between the reflective back facet of the active laser region and the first and second plate to amplify the energy, a portion of the energy causing surface plasmons to resonate in the gap, the surface plasmons directed out of the media-facing surface to form a hot spot on a recording medium while the write pole applies a magnetic field to the hotspot.