Elliptical plasmonic near-field transducer and v-shape waveguide designs for heat assisted magnetic recording

We proposed a new elliptical near-field transducer (NFT) and V-shaped waveguide design, which provides multiple pathways to control and optimise the thermal performance of the optical delivery paths for heat-assisted magnetic recording (HAMR). The principle of operation of the design utilises the properties of the localised surface plasmon resonance (LSPR) of the metallic elliptical NFT. We demonstrated a peak temperature in the recording media normalised to the incident laser power (TMedia/PIn) ranging from ∼ 128 K/mW to more than 181 K/mW. We also achieved tunable thermal gradients as high as 23.0 K/nm and 18.7 K/nm in the recording media’s down-track and cross-track directions, respectively. Moreover, we exemplified that the inevitable temperature rise in the plasmonic NFT could be tuned to remain under 400 K for maximum heat in the recording media > 700 K. The best thermal performance obtained corresponded to the aspect ratio of the antenna a/b ∼ 0.89 with the minor axis of the antenna a = 85 nm