Tilted Structures to Reduce Reflection in Laser-Assisted TAMR

摘要

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.

主权项

1. A TAMR (thermally assisted magnetic recording) head slider, comprising:
a slider substrate having a horizontal planar back end surface and a horizontal planar ABS (air bearing surface); a magnetic write element, emerging at said ABS which produces a magnetic field for writing on a magnetic recording medium rotating beneath said horizontal planar ABS end; a waveguide extending through said slider from said slider back end surface to said slider ABS end, wherein said waveguide has a dielectric core and is surrounded by a dielectric cladding, wherein said waveguide propagates optical frequency electromagnetic radiation along a centerline direction towards said slider ABS end, wherein said waveguide has a planar back end surface that is coplanar with said slider back end surface, at which back end surface said optical frequency electromagnetic radiation couples with said waveguide and; wherein said waveguide has a planar ABS end, and wherein said planar ABS end lies within said slider ABS or is tilted relative to said slider ABS end; and wherein a laser diode source of optical frequency electromagnetic radiation is affixed to said planar back end surface of said slider; wherein an exit facet of said laser diode source is electromagnetically coupled to said waveguide at said planar backside end of said waveguide; wherein said laser diode includes a resonant cavity having a central axis of symmetry; and wherein a plasmon generator is formed between said write element and said waveguide; wherein said plasmon generator has a central axis of symmetry and is positioned adjacent to said waveguide at said ABS end of said waveguide and separated from said waveguide; wherein said electromagnetic radiation is coupled to a plasmon mode in said plasmon generator; wherein said centerline direction of said waveguide at said backend surface of said waveguide is tilted relative to said central axis of symmetry of said laser diode cavity or is not tilted relative thereto; wherein said centerline direction of said waveguide is tilted relative to either said planar backside surface or said planar ABS or both said surfaces, whereby; reflections of said electromagnetic radiation, originating at interfacial surfaces and at regions of radiative coupling and proceeding in a direction back towards said laser diode are suppressed by failing to satisfy critical angle criteria set by dielectric constants of said core dielectric material and dielectric cladding material and wherein cavity modes of said laser are thereby stable.