  A near field transducer (NFT) is a key photonics component in heat assisted
magnetic recording (HAMR) for the localized heating of the magnetic medium. In
this work, we present a novel NFT design through capacitive coupling. In our
design, tapered metal bars separated by thin dielectric materials with gap
distance G are used to create the plasmonic resonance and focus the
electromagnetic field. The design is motivated by the intention to improve
thermal stability, which can be achieved through segmentation using thermally
stable dielectric material between the plasmonic metal bars. Using COMSOL
Multiphysics software, the performance of this capacitive-coupled NFT is
systematically modeled. It is shown that the electromagnetic field could
gradually be focused through the tapering towards the air bearing surface
(ABS). In addition, the focusing effect could be enhanced with a smaller NFT
peg size at the resonant wavelength. The material selection for the NFT tip
material will be discussed to further address the thermal stability of the
device. In conclusion, this capacitive-coupled NFT with dielectric separation
gaps and tapering yields an enhanced |E| field intensity at the tip with the
potential for an enhanced material thermal stability. Such a design can also
exhibit applications in other energy delivery systems as well as plasmonic
waveguides and sensors.
