Abstract
We report visualizations of the bidirectional near-field optical transfer function for a waveguide-coupled plasmonic transducer as a metrology technique essential for successful development for mass-fabricated near-field devices. Plasmonic devices have revolutionized the observation of nanoscale phenomena, enabling optical excitation and readout from nanoscale regions of fabricated devices instead of as limited by optical diffraction. Visualizations of the plasmonic transducer modes were acquired both by local near-field excitation of the antenna on the front facet of a waveguide using the focused electron beam of a scanning electron microscope as a probe of the near-field cathodoluminescence during far-field collection from the back facet of the waveguide, and by local mapping of the optical near-field for the same antenna design using scattering scanning near-field optical microscopy as a probe of the near-field optical mode density for far-field light focused into the back facet of the waveguide. Strong agreement between both measurement types and numerical modeling was observed, indicating that the method enables crucial metrological comparisons of as fabricated device performance to as-modeled device expectations for heat-assisted magnetic recording heads, which can be extended to successful development of future near-field-on-chip devices such as optical processor interconnects.
Highlights
Devices at the frontiers of nanoscience are incorporating light using optical, photonic, and plasmonic elements
Heater of the magnetic media by converting energy from far-field laser light into near-field optical modes[3,4,5,6,9]. This high-gradient optical field heats a tight spot on the magnetic media close to its Curie temperature significantly reducing its coercivity and enabling its polarization to be written by the recording head
Since the drive’s performance and the size of the recorded bit are determined by the plasmonic antenna (Fig. 1b), the success of the technology requires a thorough understanding of the antenna and waveguide coupling mechanism used for light delivery
Summary
SEM-CL measurements were performed at the Molecular Foundry using custom instrumentation with the Zeiss Supra 55VP FE-SEM with an accelerating voltage of 30 kV. Samples containing multiple HAMR heads were mounted above an optical collection fiber in a custom holder (see Supplementary Information for details). The SEM electron beam was scanned over the surface of the HAMR plasmonic antenna region to excite near-field optical modes, which coupled through the integrated optical waveguide (used for excitation in HAMR applications). The CL photons output from the fiber were coupled either to a spectrometer and CCD camera or to a photon-counting APD with a band-pass filter as the electrons were raster scanned over the antenna region. Optical CL images/maps were collected using 20 nm band-pass optical filters and a Perkin-Elmer APD (avalanche photo-diode) single-photon detector. Visualizations of the near-field modes in the region of a plasmonic device were created using scattering scanning near-field optical microscopy and scanning electron microscopy cathodoluminescence with both showing a strong correspondence to multiphysical numerical modeling of the devices under interrogation
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
