| Heat Assisted Magnetic Recording (HAMR) is one proposed method for overcoming the super-paramagnetic limit. HAMR will require integration of a complete optical path into the existing hard disk drive slider to enable sub-diffraction limit spot sizes for pushing recording densities beyond 1 Tbit/in2 . A near field transducer, called the Coupled Plasmonic Waveguide, is presented and found in simulation to heat the media within a 30 nm hot spot by 400 K for 1 mW incident on the transducer. The surface plasmon mode of the transducer is excited by evanescently coupled light from a single mode rectangular waveguide. A curved (focusing) grating coupled dielectric slab waveguide is used to transfer light from the laser source to the single mode rectangular waveguide. Variations of the optical path including straight grating couplers, waveguide tapering, symmetric and asymmetric configurations are compared. The required electrical power for the complete optical path including laser is less than 36 mW and could likely be improved to less than 3 mW using more advanced waveguide coupler designs. The thermal impact on the slider from this power dissipation is expected to be negligible. A HAMR testing system enabling recording experiments using a non-slider integrated version of the optical path is presented. This system uses thermal co-planarization to achieve the less than 10 nm separation between the near field transducer on the optical path and the recording medium and uses a double rigid architecture. |
