Abstract: A heat-assisted magnetic recording system may include, but is not limited to: at least one magnetic recording read/write head; at least one laser diode configured to illuminate at least a portion of at least one magnetic recording medium; at least one laser power level sensor configured to detect a power level of the at least one laser diode; and a controller configured to modify one or more power level settings associated with the at least one laser diode in response to one or more output signals of the at least one laser power level sensor.

Abstract: An apparatus includes a waveguide shaped to direct light to a focal point, and a near-field transducer positioned adjacent to the focal point, wherein the near-field transducer includes a dielectric component and a metallic component positioned adjacent to at least a portion of the dielectric component. An apparatus includes a waveguide shaped to direct light to a focal point, and a near-field transducer positioned adjacent to the focal point, wherein the near-field transducer includes a first metallic component, a first dielectric layer positioned adjacent to at least a portion of the first metallic component, and a second metallic component positioned adjacent to at least a portion of the first dielectric component.

Abstract: A system for stabilizing optical tape passing in front of one or more optical pickup units (OPUs) in an optical tape drive. The system includes at least one stabilizing apparatus having a pair of stabilizing members (e.g., partially convex members placed proximate each other) located opposite at least one OPU along the path of a length of optical tape. Each stabilizing member has a support portion (e.g., crown) over which the optical tape passes as the tape is being written to or read by the OPU. The support portion of one stabilizing member is spaced from the support portion of the other stabilizing member by a depression or recess over which the optical tape passes as it moves between the first and second support members. The OPU may direct laser beams at a relatively short, planar span of unsupported optical tape over the depression as part of read/write operations.

Abstract: A voice coil motor (VCM) includes a lens carrier physically connected to a magnetic device, an electromagnetic driving apparatus, constructed by a coil, a magnetic sensing element, a storage media and a controller. The magnetic sensing element detects a location of the lens carrier and outputs the location value relating to the location of the lens carrier via an amplifier. The storage media stores a gain value and an offset compensation value relating to the amplifier. The controller can make the lens carrier move between a top position and a bottom position in which the lens carrier can be moved within the voice coil motor. The lens carrier is moved using the coil interaction with a magnetic field of the magnetic device when current is applied to the coil.

Abstract: An apparatus includes a transducer including a plasmonic funnel having first and second ends with the first end having a smaller cross-sectional area than the second end, and a first section positioned adjacent to the first end of the plasmonic funnel, and a first waveguide having a core, positioned to cause light in the core to excite surface plasmons on the transducer.

Abstract: A magnetic device that includes a write pole having a write pole tip; a read pole having a read pole tip; an optical near field transducer; and a contact pad. The contact pad includes Ni100-aXa, wherein X is chosen from Ru, Re, Zr, Cr, and Cu; and a is the atomic percent of the element X, and can range from about 20 to about 90. The optical near field transducer is positioned between the read pole and the write pole and the contact pad is positioned adjacent the write pole opposite the optical near field transducer.

Abstract: According to one embodiment, there is provided a magnetic recording head which records information on a magnetic recording medium, including an ABS surface, a near-field light generating unit, a heat conducting unit, and a heat absorbing unit. The ABS surface is opposed to the magnetic recording medium. The near-field light generating unit is disposed on the ABS surface. The heat conducting unit is formed by a heat conductor disposed in contact with the near-field light generating unit. The heat absorbing unit is disposed in contact with the heat conducting unit adjacently to the near-field light generating unit in a direction along the ABS surface.

Abstract: An apparatus according to one embodiment includes a near field transducer positioned towards a media-facing surface side, a primary waveguide for delivering light to the near field transducer, a secondary waveguide positioned near the primary waveguide and configured for receiving light from a light source and transferring at least some of the light received thereby to the primary waveguide, and a gap layer positioned between the primary waveguide and the secondary waveguide, wherein the secondary waveguide includes an oxide of at least one of Ta, Ti, Zr, and Nb alloyed with an oxide of at least one of Si and Al. Additional embodiments are also disclosed.

Abstract: A waveguide that includes a first cladding layer, the first cladding layer having an index of refraction, n3; a gradient index layer positioned adjacent the first cladding layer; an assist layer positioned adjacent the gradient index layer, the assist layer having an index of refraction, n2; a core layer positioned adjacent the assist layer, the core layer having an index of refraction, n1; and a second cladding layer, the second cladding layer having an index of refraction, n4, wherein n1 is greater than n2, n3, and n4; and n2 is greater than n3 and n4.

Abstract: An optical pickup has a laser light source, beam splitter, collimator lens, reflection mirror, objective lens and photo detector are mounted in a case. An objective lens actuator includes a magnetic member and magnet. The optical pickup may become contaminated by uncured adhesive remaining at the edges of the adhesive surfaces of the magnet and the magnetic member that is transferred to the optical pickup via finger cots or tweezers, etc. In an adhesion step between the magnet and the magnetic member, in which part of a groove near to the center of the surface has a small depth and part of the groove near to the outer circumference of the surface has a large depth, an adhesive is drawn toward the center of the surface of the magnetic member by a capillary phenomenon and is prevented from spreading along the outer edge of the surface.

Abstract: A slider may have a first surface on an air bearing surface (ABS) and a laser recess formed in a second surface of the slider, opposite the first surface. A laser can then be positioned in the laser recess with the laser extending from the slider to a top plane. A stud may be formed adjacent to and separated from the laser on the second surface of the slider with the stud extending from the second surface of the slider to the top plane.

Abstract: A thermally assisted recording magnetic head is provided in which a magnetic recording medium can be irradiated with light having a spot size reduced in the submicron order with high total optical propagation efficiency. In a magnetic head, a spot size converter that propagates the light from an optical source in the magnetic head is provided adjacent to a main pole. The spot size converter includes a cover layer having a refractive index lower than that of a clad material and formed in contact with the optical waveguide core, and is formed in a shape composed of a substantially rectangular shape in a light traveling direction and a tapered shape where the width is increased toward the bottom surface of the magnetic head. The optical waveguide core having the cover layer formed is vertically interposed between multi-mode-thin-film-like cores that can excite a first or higher-order optical waveguide mode.

Abstract: A slider including a magnetic head part, an optical waveguide, and a near field element is fixed by first and second adhesives to a submount on which a semiconductor laser and a mirror are mounted, the mirror being placed at one end of the semiconductor laser in a resonance direction thereof and reflecting a laser in a direction intersecting with the resonance direction. At this time, at least parts of the first and second adhesives are applied to a position opposed to the semiconductor laser with an intermediation of the submount. The first adhesive having a higher Young's modulus than that of the second adhesive is applied onto an inflow end side of the slider including a solder connection portion, the second adhesive being applied onto an outflow end side of the slider.

Abstract: An apparatus includes a waveguide shaped to direct light to a focal point, and a near-field transducer positioned adjacent to the focal point, wherein the near-field transducer includes a dielectric component and a metallic component positioned adjacent to at least a portion of the dielectric component. An apparatus includes a waveguide shaped to direct light to a focal point, and a near-field transducer positioned adjacent to the focal point, wherein the near-field transducer includes a first metallic component, a first dielectric layer positioned adjacent to at least a portion of the first metallic component, and a second metallic component positioned adjacent to at least a portion of the first dielectric component.

Abstract: A method and apparatus for generating a laser signal for driving a laser used in thermal-assisted recording. A channel of a hard drive generates a high-frequency component of the laser signal—e.g., a periodic wave or series of pulses—and synchronizes the phase of the laser signal with a corresponding write data signal which controls the magnetization of data bits within the magnetic disk of the hard drive. The channel may be connected to a read/write integrated circuit via a channel interconnect. The read/write circuit may include a second phase control to compensate for any phase shift and an adder circuit to combine the transmitted high-frequency laser with a DC bias. Further, the read/write circuit may include a feedback loop for adjusting the DC bias based on environmental parameters of the hard drive such as temperature.

Abstract: A manufacturing method for a heat-assisted magnetic recording head includes the step of forming an internal mirror that includes a reflecting film support body and a reflecting film. The reflecting film support body includes first and second inclined surfaces. The reflecting film includes first and second portions that are located on the first and second inclined surfaces, respectively. The step of forming the internal mirror includes the step of forming the reflecting film support body and the step of forming the reflecting film. The step of forming the reflecting film support body forms an initial support body, and performs two taper-etching processes on the initial support body so that the initial support body is provided with the first and second inclined surfaces.

Abstract: A method of the invention for performing burn-in test includes assembling, on a fixture stand, a plurality of light source elements and a plurality of light detectors for monitoring a light output from a corresponding one of the plurality of light source elements; and electrifying the plurality of light source elements in a state where at least the plurality of light source elements and the plurality of light detectors are immersed in an insulation liquid. Thereby, it is realized to hold a stable temperature in a short period of time, to maintain a temperature that does not deviate from normal load conditions, and to perform a sorting test between defect parts and good part for light source unit chips without causing damage to the elements.

Abstract: The invention relates to a magneto-optical switching device for switching magnetization in a medium, comprising a magnetizable medium. According to the invention, a radiation system suited for imparting angular momentum to the magnetic spin system of said magnetizable medium, so as to selectively orient the magnetization of said medium. In addition, the invention relates to a method of switching a magnetizable medium, comprising providing a magnetizable medium; providing a radiation beam of a selectively chosen angular momentum; and targeting said radiation beam to said medium so as to transfer said angular momentum to a magnetic spin system of said magnetizable medium. Accordingly, spin states in magnetic materials can be manipulated using radiation of a suitable angular momentum. An effective magnetic field is generated for orienting the magnetization of the domains and can simultaneously be used to locally heat the material.

Abstract: A magnetic head that writes information to a recording medium includes a magnetic pole layer that generates a writing magnetic field to the recording medium, a microstripline that is disposed in proximity to the magnetic pole layer and to which high frequency current is applied, and a ferromagnetic thin film that is disposed on a portion of the microstripline that faces the recording medium, and that generates a high frequency alternate-current (AC) magnetic field to be applied to the recording medium, using a current magnetic field generated on the microstripline due to the high frequency current.

Abstract: A patterned perpendicular magnetic recording disk has a Co-alloy recording layer patterned into discrete data islands arranged in concentric tracks and exhibits a narrow switching field distribution (SFD). The disk includes a substrate, a NiTa alloy planarizing layer on the substrate, a nonmagnetic Ru-containing underlayer on the planarizing layer, an oxide-free Co alloy magnetic recording layer, and an ultrathin oxide film between the Ru-containing layer and the Co-alloy magnetic recording layer. The oxide film may be an oxide selected from a Ta-oxide, a Co-oxide and a Ti-oxide, and is ultrathin so that it may be considered a discontinuous film. The planarizing layer and ultrathin oxide film improve the growth homogeneity of the Co-alloy recording layer, so that the patterned disk with data islands shows significantly reduced SFD.

Abstract: A heat-assisted magnetic recording medium includes a substrate, a plurality of foundation layers, and a magnetic layer. The plurality of foundation layers are provided on the substrate and include a first layer containing MnO. The magnetic layer is provided on the plurality of layers and includes an alloy as a main ingredient. The alloy has an L10 structure.

Abstract: An apparatus includes a transducer assembly including a waveguide and a grating structured to couple electromagnetic radiation into the waveguide; and a body including an extended cavity vertical cavity surface emitting laser diode, and having an air bearing surface, wherein the transducer assembly is positioned adjacent to the body and the laser diode directs electromagnetic radiation onto the grating. A method of making the apparatus is also included.

Abstract: A method and system for providing an energy assisted magnetic recording (EAMR) head are described. The EAMR head includes a laser, a slider, and an EAMR transducer. The laser has a main emitter and at least one alignment emitter. The slider includes at least one alignment waveguide, at least one output device, and an air-bearing surface (ABS). The alignment waveguide(s) are aligned with the alignment emitter(s). The EAMR transducer is coupled with the slider and includes a waveguide aligned with main emitter. The waveguide is for directing energy from the main emitter toward the ABS.

Abstract: A waveguide structure for a TAMR head is disclosed wherein at least one detection waveguide is formed parallel to a main waveguide and located a gap distance therefrom. A light source transmits light into the main waveguide and towards an ABS/medium interface. A plasmon generator converts light from the waveguide into plasmon waves that are directed onto a magnetic medium. Back reflected light is captured by the main waveguide, partially diverted into a detection waveguide, and transmitted to a photo detector that measures light intensity (IB) which correlates closely to the plasmon wave intensity at the ABS/medium interface. A controller linked to the photo detector is employed to calculate IB as a function of ABS/medium spacing in a non-write condition and this relationship can be used to control and maintain a constant plasmon wave intensity at the ABS during a series of TAMR write processes with a plurality of media.

Abstract: A bit-patterned media (BPM) magnetic recording disk has discrete data islands with an exchange-coupled composite (ECC) recording layer (RL) formed of a high-anisotropy chemically-ordered FePt alloy lower layer, a lower-anisotropy Co/X laminate or multilayer (ML) upper layer with perpendicular magnetic anisotropy, wherein X is Pt, Pd or Ni, and an optional nonmagnetic separation layer or coupling layer (CL) between the FePt layer and the ML. The FePt alloy layer is sputter deposited onto a seed layer structure, like a CrRu/Pt bilayer, while the disk substrate is maintained at an elevated temperature to assure the high anisotropy field Hk is achieved. The high-temperature deposition together with the CrRu/Pt seed layer structure provide a very smooth surface for subsequent deposition of the ML (and optional CL). The separate Co/X ML has by itself a very narrow switching field distribution (SFD), so that the SFD of the ECC RL is much narrower than the SFD for the FePt layer alone.

Abstract: A thermally assisted write head having a plasmonic heating device. The plasmonic heating device has a plasmonic antenna located at an air bearing surface of the thermally assisted write head. The plasmonic antenna is constructed of an alloy that is sufficiently hard to withstand the processes such as ion milling and chemical mechanical polishing used to construct the plasmonic antenna. The plasmonic antenna is preferably constructed of AuX, where X is Cu, Ni, Ta, Ti, Zr or Pt having a concentration less than 5 atomic percent.

Abstract: A thermally assisted magnetic recording head includes a magnetic recording element part for writing, a main waveguide for assistance for receiving light, and a dummy waveguide component part provided in parallel to the main waveguide. The dummy waveguide component part includes a pair of waveguides having the same shape and dimensions including a first waveguide and a second waveguide that receive light from a back end surface opposite to an air bearing surface and guides the light toward the air bearing surface, and light emitting ends of the first waveguide and the second waveguide facing towards the air bearing surface have no shielding material, and are in a free condition so that the light intensity from the light emitting ends can be measured.

Abstract: A thermally-assisted recording (TAR) head structure has a semiconductor substrate as the head carrier with a vertical-cavity surface-emitting laser (VCSEL) on its front surface, a TAR head formed directly on the VCSEL, and a highly reflecting third mirror on its back surface. The semiconductor substrate serves as an extended cavity for the VCSEL. The TAR head is fabricated on the outer surface of the VCSEL in the same manner as proposed for fabrication of a TAR head on a conventional slider. The TAR head includes a conventional read head and write head, and an optical waveguide with a grating coupler and a near-field transducer (NFT). The laser radiation is output through a partially reflecting output mirror of the VCSEL through the front surface to the grating coupler, which turns the incoming laser radiation 90 degrees and directs it into the waveguide from where it is directed to the NFT.

Abstract: A waveguide structure for aligning a light source to a center waveguide (CWG) in a TAMR head is disclosed and includes two alignment waveguides (AWVG) symmetrically formed about a plane that bisects the CWG lengthwise dimension. Each AWVG has a light coupling section formed parallel to a side of the CWG and captures 0.5% to 10% of the light in the CWG. Each AWVG has an outlet that directs light to a photo detector or camera so that light intensity measurements lAWVG1 and lAWVG2 for first and second AWVG, respectively, can be taken at various positions of the light source. Optimum alignment occurs when (lAWVG1+lAWVG2) reaches a maximum value and |lAWVG1?lAWVG2| has a minimum value. AWVG outlets may be at the ABS, or at the side or back end of a slider. Measurement sensitivity is increased by decreasing the width of the AWVG.

Abstract: A thermally-assisted recording (TAR) bit-patterned-media (BPM) magnetic recording disk drive uses optical detection of synchronization fields for write synchronization and optical detection of servo sectors for read/write head positioning. The synchronization fields and servo sectors extend generally radially across the data tracks and are patterned into discrete nondata blocks separated by gaps in the along-the-track direction. A near-field transducer (NFT) directs laser radiation to the disk and generates a power absorption profile on the disk that has a characteristic along-the-track spot size less than the along-the-track length of the gaps between the nondata blocks in the synchronization fields and servo sectors.

Abstract: A thermally-assisted magnetic recording head that includes an air bearing surface facing a recording medium and that performs a magnetic recording while heating the recording medium includes a waveguide configured with a core through which light propagates and a cladding that surrounds a periphery of the core and that includes at least a portion extending to the air bearing surface; and a heat radiation layer that is embedded in the cladding that surrounds the periphery of the core on the air bearing surface, and that is made of a material having a higher thermal conductivity coefficient than the cladding.

Abstract: A tubular or spherical nanostructure composed of a plurality of peptides, wherein each of the plurality of peptides includes no more than 4 amino acids and whereas at least one of the 4 amino acids is an aromatic amino acid.

Abstract: An apparatus includes a waveguide including a core layer having curved edges shaped to reflect light to a focal point, and a grating positioned adjacent to or imbedded in the core layer, wherein at least a portion of the grating is positioned between the curved edges and adjacent to or imbedded in a portion of the core layer that is not traversed by light reflected from the curved edges. A data storage device that includes the apparatus is also provided.

Abstract: A near-field transducer (NFT) has a primary tip that concentrates the oscillating charge of the NFT onto a substrate, such as magnetic recording medium, to heat regions of the medium, and a secondary tip. The secondary tip is located close to a temperature sensor, such as an electrical conductor whose resistance varies with temperature. The temperature sensor senses heat from the secondary tip and thus properties of the substrate like surface topography and the presence or absence of metallic material. The NFT can be part of a bit-patterned media (BPM) thermally-assisted recording (TAR) disk drive. The temperature sensor output is used to control the write pulses from the disk drive's write head so the magnetic write field is synchronized with the location of the magnetic data islands.

Abstract: A voice coil motor (VCM) includes a lens carrier physically connected to a magnetic device, an electromagnetic driving apparatus, constructed by a coil, a magnetic sensing element, a storage media and a controller. The magnetic sensing element detects a location of the lens carrier and outputs the location value relating to the location of the lens carrier via an amplifier. The storage media stores a gain value and an offset compensation value relating to the amplifier. The controller can make the lens carrier move between a top position and a bottom position in which the lens carrier can be moved within the voice coil motor. The lens carrier is moved using the coil interaction with a magnetic field of the magnetic device when current is applied to the coil.

Abstract: Provided is a head gimbal assembly (HGA) in which the electrodes for a thermally-assisted magnetic recording head comprising a light source, a photodetector and a magnetic head element, can be reliably electrically connected to wiring members by solder ball bonding (SBB). The HGA comprises a suspension comprising: a base; a first wiring member for the light source and the photodetector, provided on a side of one surface of the base; and a second wiring member for the magnetic head element, provided on the same surface side. The first and second wiring members protrude from the base toward the head to be fixed. As a result, the end portions (connection pads) of the first and second wiring members can be located close to electrodes for light-source and photodetector and electrodes for magnetic head element, respectively. This arrangement enables the end portions of the first and second wiring members to be reliably electrically connected to the electrodes by SBB.

Abstract: A microwave assisted magnetic head is formed to include a main pole magnetic layer including a main pole; a shielded magnetic layer including a shielded pole; a recording coil that is formed to generate a writing magnetic field from a tip of the main pole; and a microwave radiation waveguide made of a conductive nonmagnetic material that is disposed in a recording gap, the recording gap being a gap between the main pole and the shielded pole.

Abstract: Disclosed is an optical device including a concave surface formed of a part of a cylindrically curved surface, and the concave surface is a reflection surface.

Abstract: Provided is a thermally-assisted magnetic recording head with improved light density of near-field light (NF-light) with which a medium is irradiated. The head comprises: a magnetic pole; a waveguide for propagating light for exciting surface plasmon; a surface plasmon generator provided between the magnetic pole and the waveguide, coupled with the light in a surface plasmon mode, and emitting NF-light; and a clad portion provided at least between the waveguide and the surface plasmon generator and comprising a transition region in which a refractive index decreases along a direction from the waveguide toward the magnetic pole. The provision of the clad portion including the transition region enables improvement of the light density of NF-light due to the convergence of surface plasmon excited in the surface plasmon generator to predetermined locations, while avoiding the problem of temperature rise due to reduction of the volume of surface plasmon generator.

Abstract: An apparatus having a transducer assembly that includes a waveguide having first and second cladding layers and a core layer between the first and second cladding layers, and a grating structured to couple electromagnetic radiation into the waveguide. The grating has a plurality of elongated slits that are substantially parallel to a longitudinal axis of the waveguide. The apparatus further has a light source mounted adjacent the waveguide to direct light onto the grating.

Abstract: A magnetic recording element that faces a recording medium and that executes a magnetic recording while the recording medium is heated, the element including a waveguide that is configured with a core and a cladding, the core, through which laser light propagates, including an enlarged part, which is enlarged at an air bearing surface facing the recording medium; and the cladding surrounding a periphery of the core.

Abstract: Provided is a thermally-assisted magnetic recording head in which a slider including an optical system is joined with a light source unit. The light source unit comprises: a unit substrate including a joining surface joined with the slider and a source-installation surface adjacent to the joining surface; a light source provided in the source-installation surface and emits light for thermal assist; and a photodetector section formed inside the unit substrate, a light-receiving portion of the photodetector section for receiving light emitted from a rear light-emission center being located on the source-installation surface side. The light source unit includes the photodetector section that enables constant monitoring of light output from the light source. Accordingly, feedback adjustment of the light output can be accomplished.

Abstract: Methods and systems for presensitizing film, including providing an assembly of heads comprising N left heads, a center head, and N right heads, each head being configured to effect a corresponding process P, on one or more regions of a film, activating the left heads and the center head sequentially over a first region of the film, in response to the head assembly moving from left to right with respect to the film, and activating the right heads and the center head sequentially over a second region of the film, in response to the head assembly moving from right to left with respect to the film.

Abstract: A method and system for providing energy assisted magnetic recording (EAMR) heads are described. The method and system include providing a substrate, at least one EAMR transducer, an overcoat layer and at least one laser. The substrate has a leading edge and a substrate trailing edge. The EAMR transducer(s) reside in a device layer and on the substrate trailing edge. The overcoat layer includes a plurality of contacts. The device layer is between the overcoat layer and the substrate trailing edge. The laser(s) provide energy to the EAMR transducer. The overcoat layer is between the substrate trailing edge and the laser(s). The laser(s) are electrically coupled to at least a first portion of the contacts. The contacts provide thermal connection through the overcoat layer and the device layer. At least a second portion of the contacts is electrically insulated from the substrate.

Abstract: An outer surface of a plasmon generator includes: a plasmon exciting part that faces an evanescent light generating surface with a predetermined distance therebetween; and a front end face located in a medium facing surface. The plasmon generator has: first and second sidewall parts that are connected to the plasmon exciting part and increase in distance from each other with increasing distance from the plasmon exciting part; and at least one extended portion connected to an edge of at least one of the first and second sidewall parts opposite from the plasmon exciting part. A magnetic pole has a portion interposed between the first and second sidewall parts. The front end face includes first and second portions lying at ends of the first and second sidewall parts and connected to each other into a V-shape. An end face of the magnetic pole has a portion interposed between the first and second portions of the front end face.

Abstract: A magnetic head includes a magnetic head slider; and a laser diode that is positioned on a surface of a side opposite to a substrate of the magnetic head slider and that generates laser light; the magnetic head slider including: a core through which the laser light emitted from the laser diode propagates as propagating light; a cladding that covers the core and that has a refractive index that is smaller than that of the core; a near field light generating means that generates near field light from the propagating light on an air bearing surface; and a main pole for recording that is disposed adjacent to the near field light generating means and of which an edge part is positioned on the air bearing surface.

Abstract: There is provided a thermally assisted magnetic recording device capable of preventing collision between a thermally assisted magnetic recording head and a disk due to thermal deformation of a near-field transducer. The thermally assisted magnetic recording device includes a temperature sensor for measuring the temperature in the vicinity of the near-field transducer, a table that stores the relationship between temperature and deformation in the vicinity of the near-field transducer, and a control unit. The control unit calculates the deformation in the vicinity of the near-field transducer, from the temperature measured by the temperature sensor and the relationship between temperature and deformation stored in the table. Then, the control unit drives the flying height control actuator according to the calculated deformation to control the distance between the thermally assisted magnetic recording and the disk in order to avoid contact between them.

Abstract: A slider mounted TAMR (Thermal Assisted Magnetic Recording), DFH (Dynamic Flying Height) type read/write head using optical-laser generated surface plasmons in a small antenna to locally heat a magnetic medium, uses the same optical laser at low power to pre-heat the antenna. Maintaining the antenna at this pre-heated temperature, approximately 50% of its highest temperature during write operations, allows the DFH mechanism sufficient time to compensate for the thermal protrusion of the antenna at that lower temperature, so that thermal protrusion transients are significantly reduced when a writing operation occurs and full laser power is applied. The time constant for antenna protrusion is less than the time constant for DFH fly height compensation, so, without pre-heating, the thermal protrusion of the antenna due to absorption of optical radiation cannot be compensated by the DFH effect.

Abstract: A curved waveguide is a curved waveguide that propagates laser light entering from the laser diode as propagating light.

Abstract: A waveguide has a core through which laser light can propagate in a TM mode, that has a rectangular cross section perpendicular to a propagative direction of the laser light, and through which the laser light can propagate in a fundamental mode in which only one portion exists on the cross section of the core where a light intensity of the laser light becomes maximal, and a higher order mode in which two or more portions exist where the light intensity becomes maximal, a clad surrounding the core, and a light absorbing element in the clad, and wherein a distance between the light absorbing element and the core is shorter than a penetration length of evanescent light in the higher order mode, but is longer than a penetration length of evanescent light in the fundamental mode.