Waveguide light delivery with subwavelength mirror for heat-assisted magnetic recording

Patent metadata

Field	Value
Publication number	US-9852753-B2
Application number	US-201615363000-A
Country	US
Kind code	B2
Filing date	Nov 29, 2016
Priority date	Feb 29, 2016
Publication date	Dec 26, 2017
Grant date	Dec 26, 2017

Abstract

A recording head has a near-field transducer proximate a media facing surface of the read/write head. A waveguide overlaps and delivers light to the near-field transducer. A subwavelength focusing mirror is at an end of the waveguide proximate the media-facing surface. The subwavelength focusing mirror recycles a residual transverse field for excitation of the near-field transducer.

First claim

What is claimed is:

1. A recording head comprising:
a near-field transducer proximate a media facing surface of the read/write head;
a waveguide that overlaps and delivers light to the near-field transducer; and
a subwavelength focusing mirror at an end of the waveguide proximate the media-facing surface, the subwavelength focusing mirror recycling a residual transverse field for excitation of the near-field transducer.

2. The recording head of claim 1 , wherein the recycling of the residual transverse fields comprises transforming the residual transverse field into a longitudinal field.

3. The recording head of claim 1 , wherein the near-field transducer extends a first distance away from the media-surface and the focusing mirror extends a second distance away from the media-surface, the second distance being less than the first distance.

4. The recording head of claim 1 , wherein the subwavelength focusing mirror comprises a maximum first cross-track width that is no more than four times a second cross-track width of the near-field transducer.

5. The recording head of claim 1 , wherein the subwavelength focusing mirror comprises a metallized, solid-immersion mirror.

6. The recording head of claim 1 , wherein the subwavelength focusing mirror comprises a parabolic mirror.

7. The recording head of claim 1 , wherein the subwavelength focusing mirror comprises one of an elliptic mirror, and an aspherical mirror.

8. The recording head of claim 1 , wherein the subwavelength focusing mirror is etched through a top cladding, bottom cladding, and core of the waveguide.

9. The recording head of claim 1 , wherein the near-field transducer comprises an enlarged portion and a peg, the peg being made of a different material than the enlarged portion.

10. The recording head of claim 1 , wherein the light is coupled into the near-field transducer in a first-higher order transverse electric mode.

11. A recording head comprising:
a near-field transducer proximate a media facing surface of the read/write head;
a waveguide that overlaps and delivers light to the near-field transducer; and
a subwavelength focusing mirror at an end of the waveguide proximate the media-facing surface, the subwavelength focusing mirror overlapping less than a length of the near-field transducer in a direction normal to the media-facing surface.

12. The recording head of claim 11 , wherein the subwavelength focusing mirror recycles residual transverse fields to boost performance of the near-field transducer.

13. The recording head of claim 12 , wherein the light is coupled into the near-field transducer in a first-higher order transverse electric and wherein the recycling of the residual transverse fields comprises transforming the residual transverse fields into longitudinal fields.

14. The recording head of claim 11 , wherein the subwavelength focusing mirror comprises a metallized, solid-immersion mirror.

15. The recording head of claim 11 , wherein the subwavelength focusing mirror comprises one of a parabolic mirror, an elliptic mirror, and an aspherical mirror.

16. The recording head of claim 11 , wherein the subwavelength focusing mirror is etched through a top cladding, bottom cladding, and core of the waveguide.

17. The recording head of claim 11 , wherein the near-field transducer comprises an enlarged portion and a peg, the peg being made of a different material than the enlarged portion.

18. A method comprising:
directing light into a waveguide core of a recording head;
coupling the light to a near-field transducer at an output end of the waveguide core near a media-facing surface of the recording head; and
recycling a residual transverse electric field component for excitation of the near-field transducer via a subwavelength mirror at the output end of the waveguide, the sub-micron mirror overlapping less than a length of the near-field transducer in a direction normal to the media-facing surface.

19. The method of claim 18 , wherein recycling the residual transverse electric field component comprises converting the residual transverse electric field to a longitudinal electrical field.

20. The method of claim 18 , further comprising applying a magnetic field to recording medium via the recording head, the near-field transducer producing a hotspot on the recording medium while the magnetic field is applied.

Assignees

• Seagate Technology Llc

Inventors

• Peng Chubing

Classifications

• G11B5/4866 Primary

  the arm comprising an optical waveguide, e.g. for thermally-assisted recording · CPC title

• G11B2005/0021

  Thermally assisted recording using an auxiliary energy source for heating the recording layer locally to assist the magnetization reversal · CPC title

• G11B5/314 Primary

  where the layers are extra layers normally not provided in the transducing structure, e.g. optical layers (G11B5/3196 takes precedence) · CPC title

• G11B5/6088

  Optical waveguide in or on flying head · CPC title