EAMR head having improved optical coupling efficiency
View Patent ↗A method and system provide an EAMR transducer having an air-bearing surface (ABS) that resides near a media during use. The EAMR transducer includes a write pole, coil(s), a near field transducer (NFT), a waveguide, and a reflective grating. The write pole writes to a region of the media. The coil(s) energize the write pole. The NFT is proximate to the ABS and focuses the energy onto the media. The waveguide is configured to direct the energy from the laser toward the NFT at an incident angle with respect to the ABS. A first portion of the energy reflects off of the ABS at a reflected angle. The reflective grating receives the first portion of the energy at the reflected angle from the ABS and reflects a second portion of the energy toward the ABS. The NFT resides between at least part of the waveguide and the reflective grating.
1. An energy assisted magnetic recording (EAMR) transducer coupled with a laser for providing energy and having an air-bearing surface (ABS) configured to reside in proximity to a media during use, the EAMR transducer comprising:
a write pole configured to write to a region of the media;
at least one coil for energizing the write pole;
a near field transducer (NFT) proximate to the ABS and for focusing the energy onto the region of the media;
a waveguide configured to direct the energy from the laser toward the NFT at an incident angle with respect to the ABS, a first portion of the energy reflecting off of the ABS at a reflected angle; and
a reflective grating configured to receive the first portion of the energy at the reflected angle from the ABS and to reflect a second portion of the energy toward the ABS, the NFT residing between at least a portion of the waveguide and the reflective grating.
2. The EAMR transducer of claim 1 wherein the reflective grating is a first order grating.
3. The EAMR transducer of claim 1 wherein the energy has an effective wavelength in the reflective grating and wherein the reflective grating has a pitch substantially equal to half the effective wavelength.
4. The EAMR transducer of claim 3 wherein the reflective grating includes a first cladding, a core, and a second cladding, an interface between the core and the second cladding having the pitch.
5. The EAMR transducer of claim 4 wherein the pitch has a tolerance of substantially two percent.
6. The EAMR transducer of claim 4 wherein the reflective grating has a duty cycle of substantially fifty percent.
7. The EAMR transducer of claim 1 wherein the incident angle is not more than a critical angle, the critical angle being such that the energy undergoes total internal reflection at the ABS.
8. The EAMR transducer of claim 1 wherein the reflective grating has a bandwidth of at least thirty nanometers.
9. The EAMR transducer of claim 1 wherein the incident angle is substantially the same as the reflected angle.
10. An energy assisted magnetic recording (EAMR) transducer coupled with a laser for providing energy and having an air-bearing surface (ABS) configured to reside in proximity to a media during use, the EAMR transducer comprising:
a write pole configured to write to a region of the media;
at least one coil for energizing the write pole;
a near field transducer (NFT) proximate to the ABS and for focusing the energy onto the region of the media;
a waveguide configured to direct the energy from the laser toward the NFT at an incident angle with respect to the ABS, a first portion of the energy reflecting off of the ABS at a reflected angle; and
a first order reflective grating configured to receive the first portion of the energy at the reflected angle from the ABS and to reflect a second portion of the energy toward the ABS, the NFT residing between at least a portion of the waveguide and the first order reflective grating, the energy having an effective wavelength in the reflective grating, the first order reflective grating including a bottom cladding, a core, and a top cladding, an interface between the core and the top cladding having a pitch, the pitch substantially equal to half the effective wavelength, the pitch having a tolerance of substantially two percent and a duty cycle of substantially fifty percent, the first order reflective grating having a bandwidth of at least thirty nanometers.
11. An energy assisted magnetic recording (EAMR) disk drive comprising:
a media for storing data;
a slider having an air-bearing surface (ABS) configured to reside in proximity to the media during use;
a laser coupled with the slider for providing energy;
an EAMR transducer coupled with the slider and including a write pole, at least one coil, a near field transducer (NFT), a waveguide, and a reflective grating, the write pole configured to write to a region of the media, the at least one coil for energizing the write pole, the NFT being proximate to the ABS and for focusing the energy onto the region of the media, the waveguide configured to direct the energy from the laser toward the NFT at an incident angle with respect to the ABS, a first portion of the energy reflecting off of the ABS at a reflected angle, the reflective grating configured to receive the first portion of the energy at the reflected angle from the ABS and to reflect a second portion of the energy toward the ABS, the NFT residing between at least a portion of the waveguide and the reflective grating.
12. The EAMR disk drive of claim 11 wherein the reflective grating is a first order grating.
13. The EAMR disk drive of claim 11 wherein the energy has an effective wavelength in the reflective grating and wherein the reflective grating has a pitch substantially equal to half the effective wavelength.
14. The EAMR disk drive of claim 13 wherein the reflective grating includes a first cladding, a core, and a second cladding, an interface between the core and the second cladding having the pitch.
15. The EAMR disk drive of claim 14 wherein the pitch has a tolerance of substantially two percent.
16. The EAMR disk drive of claim 14 wherein the reflective grating has a duty cycle of substantially fifty percent.
17. The EAMR disk drive of claim 11 wherein the incident angle is not more than a critical angle, the critical angle being such that the energy undergoes total internal reflection at the ABS.
18. The EAMR disk drive of claim 11 wherein the reflective grating has a bandwidth of at least thirty nanometers.
19. The EAMR disk drive of claim 11 wherein the incident angle is substantially the same as the reflected angle.
20. A method for providing an energy assisted magnetic recording (EAMR) transducer coupled with a laser for providing energy and having an air-bearing surface (ABS) configured to reside in proximity to a media during use, the EAMR transducer comprising:
providing a write pole configured to write to a region of the media;
providing at least one coil for energizing the write pole;
providing a near field transducer (NFT) proximate to the ABS and for focusing the energy onto the region of the media;
providing a waveguide configured to direct the energy from the laser toward the NFT at an incident angle with respect to the ABS, a first portion of the energy reflecting off of the ABS at a reflected angle; and
providing a reflective grating configured to receive the first portion of the energy at the reflected angle from the ABS and to reflect a second portion of the energy toward the ABS, the NFT residing between at least a portion of the waveguide and the reflective grating.