Direct waveguide light delivery to NFT for heat assisted magnetic recording
A magnetic recording head comprises a write pole having a pole tip adjacent to an air bearing surface, a return pole, an optical near field transducer positioned adjacent the pole tip and an air bearing surface for exposing a portion of a magnetic storage medium to high energy radiation. The energy is directly provided to the near field transducer by a ridge waveguide with tapered coupling elements, by a two dimensional straight or curved waveguide with a beveled end with a metal/dielectric coating for delivering energy to the near field transducer, or by a curved waveguide. The waveguide with tapered coupling elements or with beveled end can be fabricated by means of conventional wafer processing.
1. A magnetic recording head comprising:
a write pole having a pole tip adjacent to an air bearing surface;
a return pole;
an optical near field transducer positioned adjacent the air bearing surface and the pole tip for exposing a portion of a magnetic storage medium to near field radiation; and
a waveguide for delivering optical energy to the near field transducer, wherein the waveguide has tapered coupling elements at each end to change an optical mode of the optical energy.
2. The magnetic recording head of claim 1 , wherein the waveguide comprises a ridge waveguide.
3. The magnetic recording head of claim 2 , wherein the ridge waveguide comprises a tapered waveguide.
4. The magnetic recording head of claim 1 wherein the waveguide has a core with a multiple trapezoidal cross section.
5. The magnetic recording head of claim 3 , wherein the dimensions of a core of the tapered waveguide are reduced, from a cross-section of about 5,000 nm by about 1,000 nm to a cross-section of about 500 nm by about 200 nm, over a length of about 100micrometers.
6. The magnetic recording head of claim 1 wherein the waveguide comprises a curved waveguide.
7. The magnetic recording head of claim 1 wherein the waveguide comprises a straight waveguide.
8. The magnetic recording head of claim 7 , wherein:
the waveguide has a beveled end;
the beveled end is coated with a dielectric film and a metal film such that, when exposed to optical radiation, plasmons are excited at a metal/dielectric interface formed by the dielectric film and the metal film;
the waveguide is parallel to and proximate the optical near field transducer; and
plasmons excited at the metal/dielectric interface couple with the optical near field transducer.
9. The magnetic recording head of claim 7 , wherein the optical near field transducer is parallel to the write pole tip.
10. The magnetic recording head of claim 1 , wherein the optical near field transducer comprises a coupled nanorod.
11. A data storage device comprising:
a storage medium;
a recording head for writing data to the storage medium, the recording head including:
a waveguide for directly delivering energy to a near field transducer, wherein the waveguide has a tapered coupling element at one end to change an optical mode of the energy and a core with a rectangular or trapezoidal cross-section;
a write pole having a pole tip adjacent to an air bearing surface;
a return pole; and
an optical near field transducer positioned adjacent the air bearing surface for exposing a portion of the magnetic storage medium to high energy radiation.
12. The data storage device of claim 11 , wherein the waveguide comprises a ridge waveguide.
13. The data storage device of claim 12 , wherein the ridge waveguide comprises a tapered waveguide.
14. The data storage device of claim 11 , wherein the waveguide comprises a curved waveguide.
15. The data storage device of claim 13 , wherein the dimensions of a core of the tapered waveguide are reduced from a cross section of about 5,000 nm by about 1,000 nm to a cross section of about 500 nm by about 200 nm over a length of about 100micrometers.
16. The data storage device of claim 11 , wherein:
the waveguide has a beveled end;
the beveled end is coated with a dielectric film and a metal film such that, when exposed to optical radiation, plasmons are excited at a metal/dielectric interface formed by the dielectric film and the metal film;
the waveguide is parallel to and proximate the optical near field transducer; and
plasmons excited at the metal/dielectric interface couple with the near field transducer.
17. The data storage device of claim 16 , wherein the optical near field transducer is parallel to and proximate the writer pole of the magnetic recording head.
18. The data storage device of claim 17 , wherein the optical near field transducer comprises a coupled nanorod.
19. A device comprising:
a waveguide, parallel to and proximate an optical near field transducer, for delivering energy to the near field transducer,
wherein the waveguide has a core with a multiple trapezoidal cross section and tapered coupling elements to change an optical mode of the energy.