A heat-assisted magnetic recording (HAMR) head has a slider with a gas-bearing-surface (GBS). The slider supports a near-field transducer (NFT) and a main magnetic pole that has a step or recess in the NFT-facing surface near the GBS that contains plasmonic material. A thermal shunt is located between the NFT and the main pole to allow heat to be transferred away from the optical spot generated by the NFT. The NFT-facing surface of the main pole that is recessed from the step away from the GBS is in contact with the thermal shunt, and the thermal shunt is in contact with the plasmonic material in the step in the back region recessed from the GBS, so there is no increase in the spacing between the NFT and a large portion of the main pole.

A heat-assisted magnetic recording (HAMR) disk drive uses a semiconductor laser mounted on a slider to deliver light to a near-field transducer (NFT) via a waveguide located inside the slider. The waveguide includes a core and cladding material that is transparent to the laser light and surrounds the core. Layers of stray light absorption material are located inside the slider on opposite edges of the waveguide core in the same plane as the core and on opposite sides of the waveguide core in planes spaced from the plane of the core. Portions of the waveguide cladding material are located between the waveguide core and the stray light absorption layers. The stray light absorption layers absorb light that leaks into the cladding material and substantially reduces stray light reflected to the laser to prevent undesirable laser power fluctuation.

A heat-assisted magnetic recording (HAMR) disk drive uses a semiconductor laser mounted on a slider to deliver light to a near-field transducer (NFT) via a waveguide located inside the slider. The waveguide includes a core and cladding material that is transparent to the laser light and surrounds the core. Layers of stray light absorption material are located inside the slider on opposite edges of the waveguide core in the same plane as the core and on opposite sides of the waveguide core in planes spaced from the plane of the core. Portions of the waveguide cladding material are located between the waveguide core and the stray light absorption layers. The stray light absorption layers absorb light that leaks into the cladding material and substantially reduces stray light reflected to the laser to prevent undesirable laser power fluctuation.

Various illustrative aspects are directed to a data storage device, comprising: one or more disks; an actuator assembly comprising a head, and configured to position the head over a corresponding disk surface; and one or more processing devices, the head comprising: a write element; a laser unit; and a fly height control element, and wherein the one or more processing devices are configured to: iteratively perform spiral write operations of spiral patterns comprising a plurality of sync marks with the head on the corresponding disk surface, wherein the spiral write operations are performed at: a plurality of values of laser pre-bias current, write backoff, and/or start disk phase; detect pattern signal amplitudes of the spiral patterns on the corresponding disk surface; and determine a relation of write backoff to laser pre-bias current for the head, based on the pattern signal amplitudes of the spiral patterns.

Various illustrative aspects are directed to a data storage device, comprising: one or more disks; an actuator assembly comprising a head, and configured to position the head over a corresponding disk surface; and one or more processing devices, the head comprising: a write element; a laser unit; and a fly height control element, and wherein the one or more processing devices are configured to: iteratively perform spiral write operations of spiral patterns comprising a plurality of sync marks with the head on the corresponding disk surface, wherein the spiral write operations are performed at: a plurality of values of laser pre-bias current, write backoff, and/or start disk phase; detect pattern signal amplitudes of the spiral patterns on the corresponding disk surface; and determine a relation of write backoff to laser pre-bias current for the head, based on the pattern signal amplitudes of the spiral patterns.

A heat-assisted magnetic recording device is disposed in a hermetically sealed enclosure. The device includes a slider comprising a reader, a writer, and an optical waveguide configured to couple light from a light source to a near-field transducer situated at or near an air bearing surface of the slider. The near-field transducer comprises an enlarged portion and a peg extending from the enlarged portion in a direction of the air bearing surface. A fill gas is provided within the enclosure. The fill gas comprises a mixture of a low-density, inert gas and at least one gas that oxidizes carbon, where the total carbon oxidizing gas concentration of the fill gas is 3-50% by volume. In certain embodiments, the fill gas comprises a hydrogen concentration sufficient to retard oxidation of the peg when the peg is at an operating temperature associated with write operations.

A heat-assisted magnetic recording device is disposed in a hermetically sealed enclosure. The device includes a slider comprising a reader, a writer, and an optical waveguide configured to couple light from a light source to a near-field transducer situated at or near an air bearing surface of the slider. The near-field transducer comprises an enlarged portion and a peg extending from the enlarged portion in a direction of the air bearing surface. A fill gas is provided within the enclosure. The fill gas comprises a mixture of a low-density, inert gas and at least one gas that oxidizes carbon, where the total carbon oxidizing gas concentration of the fill gas is 3-50% by volume. In certain embodiments, the fill gas comprises a hydrogen concentration sufficient to retard oxidation of the peg when the peg is at an operating temperature associated with write operations.

A recording head has a near-field transducer proximate a media-facing surface of the recording head. A waveguide overlaps and delivers light to the near-field transducer. Two subwavelength focusing mirrors are at an end of the waveguide proximate the media-facing surface. The subwavelength mirrors are on opposite crosstrack sides of the near-field transducer and separated from each other by a crosstrack gap. The subwavelength focusing mirrors each include a core having a first edge exposed at the media-facing surface. The core formed of a core material that is resistant to mechanical wear and corrosion, such as a dielectric or robust metal. A liner covers a second edge of the core facing the near-field transducer. The liner includes a plasmonic metal that is different than the core material, such as Au or Al.

A recording head has a near-field transducer proximate a media-facing surface of the recording head. A waveguide overlaps and delivers light to the near-field transducer. Two subwavelength focusing mirrors are at an end of the waveguide proximate the media-facing surface. The subwavelength mirrors are on opposite crosstrack sides of the near-field transducer and separated from each other by a crosstrack gap. The subwavelength focusing mirrors each include a core having a first edge exposed at the media-facing surface. The core formed of a core material that is resistant to mechanical wear and corrosion, such as a dielectric or robust metal. A liner covers a second edge of the core facing the near-field transducer. The liner includes a plasmonic metal that is different than the core material, such as Au or Al.

A recording head comprises a write pole extending to an air-bearing surface. A near-field transducer is positioned proximate a first side of the write pole in a down-track direction. A heatsink structure is proximate the near-field transducer and positioned between the near-field transducer and the write pole. The heatsink structure extends beyond the near-field transducer in a cross-track direction and extends in a direction normal to the air-bearing surface.