Thermally assisted recording head utilizing laser light with limited wavelength range
View Patent ↗A thermally assisted magnetic recording head includes core that propagates laser light as propagation light, a near-field light generator that faces a portion of the core and extends to an air bearing surface (ABS), the near-field light generator coupled to the propagation light propagating through the core so as to generate a surface plasmon, propagating the surface plasmon to an end part facing the ABS, and generating near-field light at the end part to irradiate the near-field light to a magnetic recording medium, a main magnetic pole layer provided in the vicinity of the near-field light generator where an end part is positioned on the ABS, a laser diode that generates laser light of wavelength 890 nm to 1,000 nm and enters the laser light into the core, and a photodiode provided on a silicon substrate measures an intensity of the laser light entering from the laser diode to the core.
1. A thermally assisted magnetic recording head, comprising:
a main core that propagates laser light as propagation light;
a near-field light generator that faces a portion of the main core and extends to an air bearing surface, the near-field light generator being coupled to propagation light propagating through the core in a surface plasmon mode so as to generate a surface plasmon, propagating the surface plasmon to an end part facing the air bearing surface, generating near-field light at the end part so as to irradiate the near-field light to a magnetic recording medium;
a main magnetic pole layer that is provided in the vicinity of the near-field light generator and of which an end part is positioned on the air bearing surface;
a laser diode that generates laser light of wavelength 890 nm to 1,000 nm and enters the laser light into the main core; and
a photodiode that is provided on a silicon substrate and measures an intensity of the laser light entered from the laser diode to the main core, wherein
the laser diode generates TE polarization laser light and enters the TE polarization laser light from an incident part of the main core into the main core,
the main core includes a polarization direction transducer between a part facing the near-field light generator and the incident part, the polarization direction transducer converting the TE polarization laser light into TM polarization laser light that is passed as the propagation light.
2. A magnetic recording apparatus, comprising:
the thermally assisted magnetic recording head according to claim 1 ; and
a magnetic recording medium that has a magnetic recording layer and is positioned facing the air bearing surface;
wherein,
when the laser light of the wavelength of 890 nm to 1,000 nm is irradiated to the magnetic recording layer, the greater the wavelength is, the more imaginary number ingredients of the dielectric constant of materials constituting the magnetic recording layer increase.
3. The magnetic recording apparatus according to claim 2 , wherein the magnetic recording layer is formed of FePt—SiO 2 .
4. A head gimbal assembly, comprising:
the thermally assisted magnetic recording head according to claim 1 ; and
a suspension elastically supporting the thermally assisted magnetic recording head; wherein,
the suspension, comprising,
a flexure to which the thermally assisted magnetic head is bonded;
a load beam of which one end part is connected to the flexure; and
a base plate that is connected to the other end part of the load beam.
5. A magnetic recording apparatus, comprising:
the thermally assisted magnetic recording head according to claim 1 ;
a recording medium that is positioned facing the thermally assisted magnetic head;
a spindle motor that rotatably drives the recording medium; and
a positioning device that supports the thermally assisted magnetic head and that positions the thermally assisted magnetic head with respect to the magnetic recording medium.
6. The magnetic recording apparatus according to claim 1 , wherein a transducer core of the polarization direction transducer has a same cross-section as the main core.
7. The magnetic recording apparatus according to claim 1 , wherein the polarization direction transducer is located directly between the part facing the near-field light generator and the incident part.
8. The magnetic recording apparatus according to claim 1 , wherein the polarization direction transducer further comprises:
a transducer core having a same cross-section as the main core and extending in a first direction parallel to an upper surface of the transducer core; and
a ridge formed integrally with the transducer core on the upper surface of the transducer core and extending from the upper surface of the transducer core in a second direction perpendicular to the upper surface of the transducer,
wherein
first grooves are provided in the transducer core on a first side of the ridge on the upper surface of the transducer core,
second grooves are provided in the transducer core on a second side of the ridge on the upper surface of the transducer core, and
the first grooves are offset from the second grooves in the first direction.
9. A thermally assisted magnetic recording head, comprising:
a core that propagates laser light as propagation light;
a near-field light generator that faces a portion of the core and extends to an air bearing surface, the near-field light generator being coupled to propagation light propagating through the core in a surface plasmon mode so as to generate a surface plasmon, propagating the surface plasmon to an end part facing the air bearing surface, generating near-field light at the end part so as to irradiate the near-field light to a magnetic recording medium;
a main magnetic pole layer that is provided in the vicinity of the near-field light generator and of which an end part is positioned on the air bearing surface;
a laser diode that generates laser light of wavelength 890 nm to 1,000 nm and enters the laser light into the core; and
a photodiode that is provided on a silicon substrate and measures an intensity of the laser light entered from the laser diode to the core, wherein
the laser diode generates TE polarization laser light, and
the laser diode is fixed to the core so that an electric field oscillation direction of the TE polarization laser light is parallel to a normal line to a facing surface of the core, the facing surface facing the near-field light generator.
10. A magnetic recording apparatus, comprising:
the thermally assisted magnetic recording head according to claim 9 ; and
a magnetic recording medium that has a magnetic recording layer and is positioned facing the air bearing surface;
wherein,
when the laser light of the wavelength of 890 nm to 1,000 nm is irradiated to the magnetic recording layer, the greater the wavelength is, the more imaginary number ingredients of the dielectric constant of materials constituting the magnetic recording layer increase.
11. The magnetic recording apparatus according to claim 10 , wherein
the magnetic recording layer is formed of FePt—SiO 2 .
12. A head gimbal assembly, comprising:
the thermally assisted magnetic recording head according to claim 9 ; and
a suspension elastically supporting the thermally assisted magnetic recording head; wherein,
the suspension, comprising,
a flexure to which the thermally assisted magnetic head is bonded;
a load beam of which one end part is connected to the flexure; and
a base plate that is connected to the other end part of the load beam.
13. A magnetic recording apparatus, comprising:
the thermally assisted magnetic recording head according to claim 9 ;
a recording medium that is positioned facing the thermally assisted magnetic head;
a spindle motor that rotatably drives the recording medium; and
a positioning device that supports the thermally assisted magnetic head and that positions the thermally assisted magnetic head with respect to the magnetic recording medium.