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.

Methods of forming a NFT the methods including forming a hard mask positioned over at least a portion of the rod, the hard mask including at least one layer; patterning a resist mask over the hard mask, the resist mask having an edge positioned over at least a portion of the rod; etching a portion of the hard mask to expose a back edge of the rod and to form a back edge of the hard mask, wherein the back edge of the rod is equivalent to the back edge of the peg; and wherein a forward portion of the rod which is the portion of the rod forward of the back edge is covered by the hard mask; forming a disc mask including a void configured to form a disc of a NFT, the disc mask being formed over at least a portion of the hard mask so that the exposed back edge of the rod is within the void configured to form the disc; etching an area exposed in the void of the disc mask to remove both a rear portion of the rod and the surrounding dielectric up to the back edge of the hard mask edge; depositing a disc material in the etched void, wherein the back edge of the hard mask defines the front edge of the disc and the back edge of the rod is in contact with the front edge of the disc; and polishing the deposited disc material to form a top surface substantially planar with the top of the forward rod portion.

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 three dimensional magnetic recording media can consist of a coupling layer disposed between first and second vertically stacked recording layers. The coupling layer can provide exchange or antiferromagnetic coupling and allow the respective recording layers to be individually heat selected to different first and second coupling strengths through application of heat from a heat source.

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.

Data can be encoded in physical medium and represented by shapes having many various physical attributes. In various examples, data points are encoded and represented by the physical shape, color, size, and/or structure of objects. In one embodiment, holes in memory surface substrates represent data. Various attributes of such holes, including depth, profile size, profile shape, and/or angle can represent data.

An apparatus comprises a slider having an air-bearing surface (ABS), a write pole at or near the ABS, and a reader at or near the ABS and connected to a pair of reader bond pads of the slider. A near-field transducer (NFT) is formed on the slider at or near the ABS, and an optical waveguide is formed in the slider and configured to receive light from a laser source. A sensor is situated proximal of the write pole at a location within the slider that receives at least some of the light communicated along the waveguide. The sensor may be electrically coupled to the reader bond pads in parallel with the reader, and configured to generate a signal indicative of output optical power of the laser source.