A method and apparatus are directed to providing relative movement between a slider configured for heat-assisted magnetic recording and a magnetic recording medium, and causing protrusion of a portion of an air bearing surface (ABS) of the slider in response to activating at least a laser source while maintaining spacing between the protrusion and the medium. A magnitude of at least a portion of the protrusion is measured while maintaining spacing between the protrusion and the medium.

Mode hop detection is provided. A device includes circuitry to receive, from a reader element an indication of one or more properties of a magnetic medium detected by the reader element. The device includes circuitry to determine an envelope of the signal. The device includes circuitry to adjust, responsive to the envelope, a current provided to a laser configured to heat the magnetic medium.

Mode hop detection is provided. A device includes circuitry to receive, from a reader element an indication of one or more properties of a magnetic medium detected by the reader element. The device includes circuitry to determine an envelope of the signal. The device includes circuitry to adjust, responsive to the envelope, a current provided to a laser configured to heat the magnetic medium.

An apparatus comprises a slider having an air bearing surface and is configured for heat-assisted magnetic recording. The slider comprises a write pole, a near-field transducer (NFT) proximate the write pole, and an optical waveguide configured to receive light from a light source and couple the light to the NFT. The optical waveguide comprises first and second opposing major surfaces and opposing first and second edges connected to the first and second major surfaces. An optically opaque overlay is disposed on or adjacent one or both of the first and second major surfaces of the optical waveguide. Periodic structures are disposed on a surface of the optically opaque overlay facing the waveguide. The periodic structures are configured to organize stray light emanating from the waveguide for absorption by the optically opaque overlay.

A waveguide has a first cladding layer surrounding a near-field transducer. A core of the waveguide is disposed on the first cladding layer, and a second cladding layer is disposed on the core opposite the first cladding layer. A coupler is formed of a second plasmonic material and disposed in the waveguide such that a first edge of the coupler is proximate a media-facing surface and a first side of the coupler faces and is spaced apart from a peg of the near-field transducer in a downtrack direction.

An optical power level applied via a laser when recording data to a track of a heat-assisted recording medium is determined. In response to the optical power level being too low or too high, remedial action is taken to prevent loss of data on one or more of the track and an adjacent track.

An optical power level applied via a laser when recording data to a track of a heat-assisted recording medium is determined. In response to the optical power level being too low or too high, remedial action is taken to prevent loss of data on one or more of the track and an adjacent track.

An apparatus comprises a thermal sensor configured to interact with a magnetic recording disk. A head-disk interface is defined between the thermal sensor and the disk. A power supply is coupled to the thermal sensor and configured to supply a bias power to the thermal sensor between a low power and a high power. A processor is coupled to the thermal sensor and configured to determine a slope of a resistance response of the thermal sensor. The processor is further configured to detect a change in the slope relative to a baseline slope. The slope change indicates increased heat sinking between the thermal sensor and the disk due to the presence of contaminant buildup at the head-disk interface.

A solid-immersion mirror has two reflective portions surrounding a focal region. A thermal sensor that senses temperature as a function of resistance is proximate at least one of the two reflective portions of the solid-immersion mirror. A near-field transducer is located proximate the focal region of the solid-immersion mirror. The near-field transducer directs optical energy to a magnetic recording medium.

An apparatus includes a near-field transducer (NFT) of a heat-assisted magnetic recording head. The NFT includes a substantially C-shaped portion and a peg portion extending from the substantially C-shaped portion. A planar member is disposed adjacent the NFT. The planar member includes a bottom surface configured to support surface plasmon polaritons (SPPs) that resonantly excite the NFT. A barrier member is installed within the planar member and is arranged to encompass at least a tip portion of the peg.