Abstract: An apparatus comprises a slider configured for heat-assisted magnetic recording comprising an air bearing surface (ABS). The slider comprises a write pole at or near the ABS, and a near-field transducer (NFT) at or near the ABS and proximate the write pole. A main waveguide is configured to receive light from a laser source and communicate the light to the NFT. An optical power sensor comprises a tap waveguide optically coupled to the main waveguide and comprising a first end and an opposing second end. The optical power sensor also comprises a bolometer optically coupled to the tap waveguide and configured to receive a portion of the light extracted from the main waveguide by the tap waveguide.

Abstract: A recording head has a light source that emits light at a wavelength in a wavelength range of 260 nm to 460 nm inclusive. A slider body of the light source includes a magnetic pole extending to a media-facing surface of the recording head and integrated photonics that deliver the light to a recording medium. The integrated photonics include a waveguide that couples the light from the light source to the media-facing surface of the slider and a near-field transducer coupled to receive the light from the waveguide. The near-field transducer has a surface plasmon plate and a peg extending from the surface plasmon plate. The surface plasmon plate is formed of a first material having a first plasmonic quality factor (Q-factor) above 5 in the wavelength range, the peg formed of a second material having a second Q-factor above 1.2 in the wavelength range.

Abstract: A folded lasing cavity comprises at least one bend. The folded lasing cavity is disposed on and configured to emit light along a substrate-parallel plane. An etched facet is on an emitting end of the folded lasing cavity and an etched mirror is on another end of the folding lasing cavity. An etched shaping mirror redirects light received from the etched facet in a direction normal to the substrate-parallel plane.

Abstract: A near-field transducer is situated at or proximate an air bearing surface of the apparatus and configured to facilitate heat-assisted magnetic recording on a medium. The near-field transducer includes an enlarged region comprising plasmonic material and having a first end proximate the air bearing surface. The near-field transducer also includes a disk region adjacent the enlarged region and having a first end proximate the air bearing surface. The disk region comprises plasmonic material. A peg region extends from the first end of the disk region and terminates at or proximate the air bearing surface. The near-field transducer further includes a region recessed with respect to the peg region. The recessed region is located between the peg region and the first end of the enlarged region.

Abstract: A heat assisted magnetic recording head gimbal assembly comprises a light source unit, a heat assisted magnetic recording head, a suspension, an actuator, and a slider. The light source unit comprises a light emitting element and a submount. The suspension comprises a load beam and a flexure movably coupled with the load beam. The actuator is deformably coupled to the flexure. The slider is supported by the suspension and coupled to the flexure and the light source unit. The slider includes the heat assisted magnetic recording head. First and second solders or conductive adhesives are positioned on opposite longitudinal sides of the light source unit, so that the first solder or conductive adhesive electrically and mechanically connects the submount to a wiring supplying power, while the second solder or conductive adhesive electrically and mechanically connects the light emitting element to the wiring.

Abstract: A heat-assisted magnetic recording (HAMR) write apparatus includes a laser for providing energy and resides in proximity to a media during use. The HAMR write apparatus includes a write pole that writes to a region of the media, coil(s) for energizing the write pole and a waveguide optically coupled with the laser. The waveguide includes at least one multi-mode interference (MMI) device. The MMI device has at least one input, a plurality of outputs, a propagation section and a multi-mode interference (MMI) section. Energy from the laser propagates through the propagation section before the MMI section. The propagation section expands the energy from the laser to a plurality of modes. A first portion of the outputs is output from the propagation section. The MMI section is between the propagation section and a second portion of the plurality of outputs.

Abstract: An apparatus comprises a slider having a trailing edge and a leading edge. A laser diode unit comprises a submount and a laser diode mounted to the submount. The submount includes a mounting surface affixed to a first surface of the slider at the trailing edge such that a first surface of the submount faces toward the leading edge of the slider. A thermally conductive material covers the first surface of the submount and at least a portion of the first surface of the slider. The thermally conductive material serves as a thermal conduction pathway between the submount and the slider.

Abstract: A viewing device is disclosed. The device includes a projector that projects a first imaged light, and a polarizing beam splitter plate that receives the projected first imaged light from the projector and reflects the received first imaged light for viewing by a viewer. The polarizing beam splitter plate also receives a second image and transmits the second image for viewing by the viewer. The polarizing beam splitter plate includes a substrate and a multilayer optical film reflective polarizer that is adhered to the substrate. The reflective polarizer substantially reflects polarized light having a first polarization state and substantially transmits polarized light having a second polarization state perpendicular to the first polarization state. The polarizing beam splitter plate includes a first outermost major surface and an opposing second outermost major surface that makes an angle of less than about 20 degrees with the first outermost major surface.

Abstract: A heat assisted magnetic recording (HAMR) writer is described. The HAMR writer is coupled with a laser that provides energy having a first polarization state. The HAMR writer has an air-bearing surface (ABS) configured to reside in proximity to a media during use, a plurality of waveguides, a main pole and at least one coil. The main pole writes to the media and is energized by the coil(s). The waveguides receive the energy from the laser and direct the energy toward the ABS. The waveguides include an input waveguide and an output waveguide. The input waveguide is configured to carry light having the first polarization state. The output waveguide is configured to carry light having a second polarization state different from the first polarization state. The waveguides are optically coupled and configured to transfer the energy from the first polarization state to the second polarization state.

Abstract: A method of forming a TAMR (Thermal Assisted Magnetic Recording) write head that uses the energy of optical-laser excited plasmons to locally heat a magnetic recording medium and reduce its coercivity and magnetic anisotropy. The magnetic field of the write head is enhanced by the formation of a leading shield that is formed in a concave geometrical shape and partially surrounds the waveguide portion of the head within the concavity, which allows the distal end of the waveguide to extend to the ABS plane of the write head. This arrangement reduces the gap between the shield and the magnetic pole and does not interfere with the ability of the waveguide to efficiently transfer its optical energy to the plasmon generator and, ultimately, to the surface of the magnetic recording medium.

Abstract: Disclosed are plasmonic near-field transducers that are useful in heat-assisted magnetic recording. The disclosed plasmonic near-field transducers have an enlarged region and a flared region. In some embodiments the disclosed plasmonic near-field transducer can also include a peg region. The flared region can act as a heat sink and can lower the thermal resistance of the peg region of the near-field transducer, thus reducing its temperature. Also disclosed are methods that include delivering light to a magnetic transducer region via a waveguide, receiving the light at a plasmonic near-field transducer having an output end and disposed in proximity to the magnetic transducer region, and delivering a surface plasmon-enhanced near-field radiation pattern proximate the output end of the plasmonic transducer in response to receiving the light.

Abstract: An apparatus that includes a near field transducer, the near field transducer including silver (Ag) and at least one other element or compound, wherein the at least one other element or compound is selected from: copper (Cu), palladium (Pd), gold (Au), zirconium (Zr), zirconium oxide (ZrO), platinum (Pt), geranium (Ge), nickel (Ni), tungsten (W), cobalt (Co), rhodium (Rh), ruthenium (Ru), tantalum (Ta), chromium (Cr), aluminum (Al), vanadium (V), iridium (Ir), titanium (Ti), magnesium (Mg), iron (Fe), molybdenum (Mo), silicon (Si), or combinations thereof oxides of V, Zr, Mg, calcium (Ca), Al, Ti, Si, cesium (Ce), yttrium (Y), Ta, W or thorium (Th), Co, or combinations thereof; or nitrides of Ta, Al, Ti, Si, indium (In), Fe, Zr, Cu, W, boron (B), halfnium (Hf), or combinations thereof.

Abstract: A method of mitigating an effect of track misregistration on read performance in a system comprising an array-reader includes determining an estimated off-track condition, selecting translation coefficients based on the estimated off-track condition, determining updated equalizer coefficients by applying the translation coefficients to native equalizer coefficients, and applying the updated equalizer coefficients to signals received from the array-reader to output a read signal.

Abstract: A bottom surface of an optical component is bonded to a mounting surface. The bottom surface includes a first opaque feature and the mounting surface includes a second opaque feature. The first and second opaque features are hidden between the bottom surface and the mounting surface after the bonding. An infrared image is obtained through a top surface of the optical component that is opposed to the bottom surface. The infrared image includes a view of a region proximate first and second opaque features. One or more of an optical alignment and a bond line thickness between the optical component and the mounting surface is determined via the infrared image.

Abstract: A method of manufacturing a thermally-assisted magnetic head includes providing a light source unit including a laser diode; providing a reflection board, and a photo detector; driving the laser diode to emit a light beam towards the reflection board; performing an alignment between the light source unit and the thermally-assisted magnetic recording head section, based on a reflected light of the light beam reflected by the reflection board, then passed through the optical waveguide and finally detected by the photo detector obtaining the maximum power in a LED emission state of the laser diode; and bonding the light source unit to the slider after the alignment is completed. It improves alignment accuracy between a light source unit and a slider during a bonding process therebetween, prevents a laser diode of the light source unit instability, and improves performance of the thermally-assisted magnetic head finally.

Abstract: An apparatus comprises a writer, a near-field transducer (NFT), a channel waveguide proximate the NFT, a dielectric layer between the NFT and waveguide, and a plurality of heat sinks. A first heat sink comprises a gap and contacts the NFT and the writer. A second heat sink extends across the gap of the first heat sink and between the NFT and a heat reservoir component, such as a return pole of the writer. The channel waveguide may contact the second heat sink, such as by encompassing a peripheral portion of the second heat sink. The second heat sink may have at least an outer surface comprising a plasmonic material, and may be configured to enhance plasmonic excitation of the NFT.

Abstract: Embodiments of the present invention generally relate to a HAMR head including a near field transducer having an antenna, a surface diffusion inhibitor layer disposed on a portion of the antenna and an aperture disposed over the surface diffusion inhibitor layer. The surface diffusion inhibitor layer has a greater melting point than the antenna, and the surface diffusion inhibitor layer material is immiscible in the antenna material.

Abstract: A near-field transducer includes an enlarged transducer portion of plasmonic material extending from an input end to an output end, a surface of the transducer portion including a trench running between two raised portions of the plasmonic material, the trench extending at least partially from the input end to the output end. A peg of the plasmonic material is disposed on the output end of the transducer portion and extends from the output end toward the air bearing surface of a heat assisted magnetic recording slider.

Abstract: In a heat-assisted magnetic recording hard disk drive, a laser module includes a submount-integrated photodetector configured to receive optical energy from a laser by way of a head slider. The submount may be formed of a semiconductor material such as a crystalline silicon material, and the photodetector may be a photodiode that is integrally formed with the submount. A HAMR head slider may comprise a feedback waveguide configured to guide optical energy from the laser through the slider to a feedback photodiode at an interface of the submount and the slider, to detect the optical energy transmitted through the slider to the slider air bearing surface (ABS). A back facet photodiode may also be integrally formed with the submount and configured to receive back facet optical energy to detect the optical energy generated by the laser.

Abstract: Controlling a laser diode involves activating a first current source in preparation for writing to a magnetic recording medium. The first current source applies a threshold current to a laser diode that brings the laser diode close to an operating point. Responsive to a write signal, a second current source is activated that applies a write current to the laser diode. A combination of the write current and the threshold current fully energizes the laser diode and is less than a target recording current. Coincident with the activation of the second current source, a photodiode is activated that is optically coupled to the laser diode. The activated photodiode causes a feedback current to be applied to the laser diode.

Abstract: A waveguide is configured to couple light from a light source at a fundamental transverse electric (TE) mode. A mode converter outputs the light to an output region of the waveguide at a higher-order TE mode. A plasmonic transducer receives the light at the higher order TE mode and generates surface plasmons that heat a recording medium. The plasmonic transducer includes: an input end proximate the output region of the waveguide and comprising a first convex curved edge; an output end proximate a surface that faces the recording medium, the output end comprising a second convex curved edge and a peg; and linear edges between the first and second convex curved edges.

Abstract: The present invention relates to a plasmon generator, in which a surface plasmon is excited by application of light. The plasmon generator extends along one direction. The plasmon generator includes a first end surface that is positioned on one end in the one direction and at which near-field light is generated along with the excitation of the plasmon; and a second cross section that is substantially parallel to the first end surface and is away from the first end surface. The first end surface has a polygonal shape that does not have a substantially acute inner angle. The second cross section has an upper part that has a shape substantially the same as or similar to that of the first end surface and a flare shaped lower part that is connected to the upper part and has a width that increases as it is far from the upper part.

Abstract: An apparatus includes a write element configured to apply a magnetic field to write data on a portion of a heat-assisted magnetic recording media in response to an energizing current. An energy source is configured to heat the portion of the media being magnetized by the write element. A preheat energizing current is applied to the write element during an interval before writing the data to the portion of the media. The preheat energizing current does not cause data to be written to the media and brings at least one of the write element and driver circuitry into thermal equilibrium prior to writing the data on the portion.

Abstract: A TAMR (Thermal Assisted Magnetic Recording) write head uses the energy of optical-laser excited surface plasmons in a plasmon generator to locally heat a magnetic recording medium and reduce its coercivity and magnetic anisotropy. The optical radiation is transmitted to the plasmon generator by means of a waveguide, whose optical axis (centerline) is tilted relative to either or both the backside surface normal and ABS surface normal in order to eliminate back reflections of the optical radiation that can adversely affect the properties and performance of the laser. Variations of the disclosure include tilting the plasmon generator, the waveguide and the laser diode.

Abstract: A recording head for recording information on a rotating recording medium of a storage device includes a main magnetic pole which generates a recording magnetic field in a direction perpendicular to a recording medium facing surface of the magnetic recording head, and a light generating element which is provided on a leading side of the main magnetic pole, and generates light for heating the recording layer of the recording medium. The main magnetic pole includes an end surface facing the light generating element that is inclined with respect to the direction perpendicular to the recording medium facing surface toward the light generating element.

Abstract: In a heat-assisted magnetic recording (HAMR) hard disk drive, a heat-dissipating head slider assembly is described in which the slider is stepped on the disk-opposing side and a HAMR laser module is mounted on the lower surface to assist with dissipation of heat from the laser. The lower surface is a surface of the main body of the slider and is composed primarily of a first material, and the slider may include a heat-dissipating plate that forms the higher stepped surface, where the plate is composed of a second material that has a higher thermal conductivity than the first material, such as silicon.

Abstract: A heat assisted magnetic recording (HAMR) transducer on a slider and including first and second opposing surfaces, wherein the first surface is aligned to an air bearing surface (ABS) of the slider and the second surface is aligned to a surface of the slider opposite the ABS, a target waveguide having an entrance at the second surface, the target waveguide being configured to direct energy provided by a light source from the entrance toward the first surface, wherein the target waveguide expands in cross-section area with distance from the entrance to form an inverse taper waveguide, a plurality of assistant waveguides each having an entrance at the second surface, wherein the plurality of assistant waveguides are configured to direct energy to the plurality of output devices.

Abstract: A method of manufacturing a thermally-assisted magnetic recording head includes the steps of: forming a preliminary head section that has a surface to be polished and includes a magnetic pole, a waveguide, and a preliminary plasmon generator; causing a volumetric expansion of the preliminary plasmon generator with heat by introducing light into the core of the waveguide of the preliminary head section; and polishing the surface to be polished of the preliminary head section into a medium facing surface. The preliminary plasmon generator has an end face located in the surface to be polished. In the step of polishing the surface to be polished, the surface to be polished is subjected to polishing with the preliminary plasmon generator expanded in volume, whereby the end face of the preliminary plasmon generator is polished into the front end face, and the preliminary plasmon generator thereby becomes the plasmon generator.

Abstract: A data storage media may have at least a multi-layer recording lamination with a predetermined coercivity. The multi-layer recording lamination can be configured to record at least one servo format mark for a plurality of data tracks with a solid immersion mirror and program a data bit on the multi-layer recording lamination with a near field transducer.

Abstract: An HAMR NFT pin and main body structure comprising a pin material with high index of refraction and low absorption coefficient is disclosed. The disclosed NFT pin provides a comparable media absorption efficiency to the conventional Au pin while improving on overall NFT reliability. The protrusion of the NFT pin is reduced and overall life of the writer is prolonged. The main body may comprise any noble metal or metal alloy suitable for achieving optical resonance in an HAMR NFT. The cladding material may be selected such that its coefficient of thermal expansion closely matches the coefficient of thermal expansion of the pin material.

Abstract: A method and system provides an EAMR transducer. The transducer is coupled with a laser for providing energy and has an air-bearing surface (ABS) configured to reside in proximity to a media during use. The EAMR transducer includes a composite near field transducer (NFT), a write pole and at least one coil for energizing the write pole. The write pole is configured to write to a region of the media. The composite NFT is for focusing the energy onto the region of the media. The composite NFT includes at least one metal and at least one insulator therein.

Abstract: Light is guided from a light source into a waveguide coupler embedded in a slider. The light source is capable of being positioned in a cross-track, a down-track, and a vertical direction with regards to the waveguide coupler. The light emanating from an air-bearing surface of the slider is imaged using a device that generates an optical image of the air-bearing surface. A cross-track alignment position is identified as a location at which the image shows substantially the same number of photons on each side of the cross-track alignment position and has a minimum spread. A down-track alignment position is identified at which the light emanating from the air-bearing surface has maximal intensity in a down-track direction.

Abstract: An apparatus includes a submount having a mounting surface and a top surface opposite the mounting surface. A slider has a bonding feature that interfaces with the mounting surface of the submount, and two or more layers are disposed between the mounting surface of the submount and the bonding feature. The two or more layers are configured to enhance light absorption of light in proximity to the bonding feature. The light originates from a source of electromagnetic energy that illuminates the top surface of the submount.

Abstract: Embodiments of the present invention generally relate to a method for forming a HAMR device having a photonic integrated circuit that includes an optical detector, an optical emitter, and an optical element distinct from the optical detector and the optical emitter, where the elements of the photonic integrated circuit are aligned with a near field transducer. The method includes forming one or more layers on a substrate, bonding the layers to a partially fabricated recording head, removing the substrate using epitaxial lift-off, and forming the optical elements on the partially fabricated recording head.

Abstract: The magnetic recording medium is a particulate magnetic recording medium for heat-assisted recording, as well as includes a magnetic layer comprising ferromagnetic powder and binder on a nonmagnetic organic material support and a heat-diffusing layer of higher thermal conductivity than the magnetic layer between the nonmagnetic organic material support and the magnetic layer.

Abstract: An apparatus includes an input region having a high-refractive-index material and an input surface configured to receive light emitted from a laser. An output surface of the apparatus is configured to deliver energy to a recording medium. The apparatus includes a plasmonic waveguide having a first elongated portion at an angle to the input surface and configured to receive the light through the input region. In response to receiving the light, surface plasmons are excited and guided to an end of the first elongated portion. The plasmonic waveguide includes a second elongated portion coupled to the end of the first elongated portion and configured to guide the surface plasmons to the output surface.

Abstract: Apparatus and method for recovering data from a multi-channel input signal, such as but not limited to a readback signal from a bit patterned medium (BPM) having a plurality of subtracks. In accordance with some embodiments, a single input single output (SISO) equalizer is adapted to generate equalized outputs responsive to alternating subchannels of the multi-channel input signal. A detector is adapted to generate estimates of data symbols represented by the input signal responsive to the equalized outputs. A switching circuit is adapted to switch in different equalizer coefficients for use by the SISO equalizer for each of the alternating subchannels in the input signal.

Abstract: An apparatus includes a submount having a mounting surface and a top surface opposite the mounting surface. A slider has a bonding feature that interfaces with the mounting surface of the submount, and two or more layers are disposed between the mounting surface of the submount and the bonding feature. The two or more layers are configured to enhance light absorption of light in proximity to the bonding feature. The light originates from a source of electromagnetic energy that illuminates the top surface of the submount.

Abstract: A TAMR (Thermal Assisted Magnetic Recording) write head uses the energy of optical-laser excited surface plasmons in a plasmon generator to locally heat a magnetic recording medium and reduce its coercivity and magnetic anisotropy. The optical radiation is transmitted to the plasmon generator by means of a waveguide, whose optical axis (centerline) is tilted relative to either or both the backside surface normal and ABS surface normal in order to eliminate back reflections of the optical radiation that can adversely affect the properties and performance of the laser. Variations of the disclosure include tilting the plasmon generator, the waveguide and the laser diode.

Abstract: A heat-assisted magnetic recording (HAMR) transducer is coupled with a laser for providing energy and has an air-bearing surface (ABS) configured to reside in proximity to a media during use. The HAMR transducer includes a write pole, at least one coil, a waveguide optically coupled with the laser and a grating. The write pole is configured to write to a region of the media. The coil(s) energize the write pole. The waveguide includes arms that have an optical path difference. The grating is optically coupled with the laser. The waveguide is optically coupled with the grating and receives light from the grating.

Abstract: A method and system provide an energy assisted magnetic recording (EAMR) disk drive. The EAMR disk drive includes a media, at least one laser coupled with the slider, at least one EAMR head on the slider, and at least one electro-optical modulator (EAM) The EAM(s) are optically coupled with the laser(s) and coupled with the slider. The combination of the laser(s) and EAM(s) provide a pulsed energy output. The EAMR head(s) include at least one waveguide, a write pole, and at least one coil for energizing the write pole. The waveguide(s) receive the pulsed energy output and direct the pulsed energy output toward the media.

Abstract: An apparatus includes a solid immersion mirror with opposing, reflective, inner sidewalls having inner surfaces facing a focal region and outer surfaces opposite the inner surfaces. The solid immersion mirror also include opposing outer sidewalls spaced apart from and facing the outer surfaces of the inner sidewalls, and a fill material between the inner sidewalls and outer sidewalls. The apparatus also includes a near-field transducer located in the focal region proximate a media-facing surface.

Abstract: A light delivery system in a slider includes a channel waveguide, a mode-index refractive surface, a solid immersion mirror, and a near field transducer. The mode-index refractive surface shapes the angular spectrum of the light on its path to the solid immersion mirror in a manner so as to change the distribution of light energy focused on to the near field transducer.

Abstract: A magnetic write head is disclosed that includes a slider that includes a laser diode having a light-emitting edge or surface of a laser diode and an optical waveguide. The disclosed magnetic write head also includes a dielectric layer disposed in a gap between the laser diode and an input to the optical waveguide. The dielectric layer fills the gap completely and provides a low-loss optical pathway for the laser diode to the input of the optical waveguide. Also disclosed is a method that includes spinning on a dielectric in a gap between the light-emitting surface and the optical waveguide coupler, wherein after the spinning on, the laser diode is optically coupled to the optical waveguide coupler through the dielectric.

Abstract: A write head includes a cavity configured to couple a laser diode to the write head. A bottom of the cavity includes a heat conductive element configured to contact the laser diode, a plurality of thermal studs disposed below the heat conductive element, and a substrate disposed below the thermal studs. The heat conductive element, thermal studs, and substrate are thermally coupled to draw heat from the laser diode.

Abstract: Systems and methods for providing thermal barrier bilayers for heat assisted magnetic recording (HAMR) media are provided. One such HAMR medium includes a substrate, a heat sink layer on the substrate, a thermal barrier bilayer on the heat sink layer, the bilayer comprising a first thermal barrier layer on the heat sink layer and an amorphous underlayer on the first thermal barrier layer, and a magnetic recording layer on the amorphous underlayer, wherein a thermal conductivity of the first thermal barrier layer is less than a thermal conductivity of the amorphous underlayer.

Abstract: A plasmon generator has a front end face, a first metal layer, a second meta-field light based on a surface plasmon. The intermediate layer is interposed between the first metal layer and the second metal layer. Each of the first metal layer, the second metal layer and the intermediate layer has an end located in the front end face. Each of the first and second metal layers is formed of a metal material. The intermediate layer is formed of a material higher in Vickers hardness than the metal material used to form the first metal layer and the metal material used to form the second metal layer.

Abstract: A heat-assisted magnetic recording (HAMR) transducer is coupled with a laser for providing energy and has an air-bearing surface (ABS) configured to reside in proximity to a media during use. The HAMR transducer includes a waveguide optically coupled with the laser and an optical power monitor optically coupled with the waveguide. The waveguide directs energy from the laser toward the media. The optical power monitor is optically coupled with the waveguide. The optical power monitor for captures a portion of the energy, converts the portion of the energy to heat and measures a local temperature proximate to the optical power monitor.

Abstract: Apparatus and systems create differential drive signals suitable for HAMR data recording. A laser diode differential driver provides heating current pulses at a time ?1. The pulses energize a laser diode to pre-heat the magnetic medium to be written. Some embodiments duplicate portions of the laser diode circuit architecture to create a magnetic write head differential driver. The write head driver provides write current pulses to a magnetic write head in one direction with ?1 timing and in the opposite direction with ?2 timing. Both drivers utilize sets of reference voltages capable of being switched to one terminal or the other of the element to be driven. In the laser diode case, the common mode is split between the anode and cathode sections of the driver. A feedback element is added between the cathode and anode sections to provide current accuracy independent of the electrical characteristics of the selected laser diode.

Abstract: Techniques for improving the recording quality during heat assisted magnetic recording (HAMR) by monitoring the power of a source used to heat a storage medium are described. In one example, a source emits electromagnetic radiation. A waveguide transmits the electromagnetic radiation onto a surface of a magnetic media. A photoresistive material is proximately located to the waveguide. The resistance of the photoresistive material varies based on the intensity of electromagnetic radiation propagating through the waveguide. The power of the source is determined by measuring the resistance of the photoresitive material. The power of the source is adjusted based on the determined power.