An apparatus includes an input coupler configured to receive light excited by a light source. A near-field transducer (NFT) is positioned at a media-facing surface of a write head. A layered waveguide is positioned between the input coupler and the NFT and configured to receive the light output from the input coupler in a transverse electric (TE) mode and deliver the light to the NFT in a transverse magnetic (TM) mode. The layered waveguide comprises a first layer extending along a light-propagation direction. The first layer is configured to receive light from the input coupler. The first layer tapers from a first cross track width to a second cross track width where the second cross track width is narrower than the first cross track width. The layered waveguide includes a second layer that is disposed on the first layer. The second layer has a cross sectional area in a plane perpendicular to the light propagation direction that increases along the light propagation direction. The cross sectional area of the second layer is smaller proximate to the input coupler and larger proximate to the NFT.

Devices having an air bearing surface (ABS), the device including a near field transducer, the near field transducer having a peg and a disc, the peg having a region adjacent the ABS, the peg including a plasmonic material selected from gold (Au), silver (Ag), copper (Cu), ruthenium (Ru), rhodium (Rh), aluminum (Al), or combinations thereof; and at least one other secondary atom selected from germanium (Ge), tellurium (Te), aluminum (Al), antimony (Sb), tin (Sn), mercury (Hg), indium (In), zinc (Zn), iron (Fe), copper (Cu), manganese (Mn), silver (Ag), chromium (Cr), cobalt (Co), and combinations thereof, wherein a concentration of the secondary atom is higher at the region of the peg adjacent the ABS than a concentration of the secondary atom throughout the bulk of the peg, and a method of forming NFT thereof.

A slider of a heat-assisted recording head comprises electrical bond pads coupled to bias sources and a ground pad, an air bearing surface, and a waveguide configured to receive light from a laser source. A contact sensor proximate the air bearing surface is coupled between a first bond pad and a second bond pad. A bolometer is coupled to a reference thermal sensor. The bolometer is situated at a slider location that receives at least some of the light communicated along the waveguide. The reference thermal sensor is situated at a slider location unexposed to the light communicated along the waveguide. The bolometer and reference thermal sensor are coupled between the first and second bond pads and in parallel with the contact sensor. A ground connection is coupled to the ground pad and at a connection between the bolometer and the reference thermal sensor.

A data storage device is disclosed comprising a head actuated over a disk, wherein the head comprises a laser configured to heat the disk while writing data to the disk. At least four different laser powers are applied to the laser and a fly height of the head over the disk is measured at each laser power. A lasing threshold power for the laser is detected based on the measured fly heights.

A data storage device is disclosed comprising a head actuated over a disk, wherein the head comprises a fly height actuator (FHA). A FHA control signal is applied to the FHA, wherein the FHA control signal comprises a DC component and an AC component. A fly height metric is measured representing a fly height of the head over the disk for different levels of the DC component. A modulation amplitude of the fly height metric is detected, and a minimum in the modulation amplitude of the fly height metric is detected.

A first waveguide core is configured to receive light via an input surface. The first waveguide core extends away from the input surface in a light propagation direction and terminates at a coupling region. A second waveguide core has a first end at the coupling region and a second end at a media-facing surface that is opposed to the input surface. The first end is separated from the termination of the first waveguide core by a gap in the coupling region. The coupling region includes an overlap between the first and second waveguide cores and is configured to promote evanescent coupling between the first and second waveguide cores.

A method for fabricating a near-field transducer (NFT) for a heat assisted magnetic recording (HAMR) write apparatus is described. The HAMR write apparatus is coupled with a laser for providing energy and has a media-facing surface (MFS) configured to reside in proximity to a media during use. The method includes providing a stack on an underlayer. The stack includes an endpoint detection layer, an optical layer and an etchable layer. The optical layer is between the etchable and endpoint detection layers. The etchable layer is patterned to form a mask. A portion of the optical layer is removed. A remaining portion of the optical layer has a bevel at a bevel angle from the MFS location. The bevel angle is nonzero and acute. The NFT is provided such that the NFT has an NFT front surface adjoining the bevel and at the bevel angle from the MFS location.

A thermal assisted magnetic recording head that performs magnetic recording while locally heating a magnetic recording medium includes: a plasmon generator that generates a surface plasmon and that generates near-field light from the surface plasmon on a front end surface positioned on an air bearing surface opposing the magnetic recording medium; a dielectric body layer positioned around the plasmon generator; and an adhesion layer positioned between the plasmon generator and the dielectric body layer. The adhesion layer is made from at least one of IrOx, RuOx, NiOx and CoOx.

A system, according to one embodiment, includes: a near field transducer, a return pole, a main pole, a waveguide adjacent the near field transducer, wherein the waveguide extends away from the near field transducer along a direction perpendicular to a media facing surface, at least one cladding layer adjacent to the waveguide, an underlayer positioned behind the near field transducer with respect to the media facing surface, the underlayer extending away from the near field transducer along the direction perpendicular to the media facing surface, and a fill material at least partially surrounding the underlayer, the waveguide and the at least one cladding layer. The underlayer has a lower coefficient of thermal expansion than the fill material. Other systems, and methods are described in additional embodiments,

A system for compensating for heat induced transient phase shift in a heat assisted magnetic recording system. A heat assisted magnetic data recording system includes a near field thermal transducer that locally heats the media during writing. The thermal transducer, when activated, results in a change in size of a magnetic transition written to the magnetic media. This change in size of the thermal transition results in a transient phase shift of the data recorded on the magnetic media. The system includes circuitry for predetermining an anticipated amount of transient phase shift and adjusting a subsequent read signal to compensate for the known transient phase shift, thereby eliminating signal errors resulting from the transient phase shift.