Simulation on near-field light on recording medium generated by semiconductor ring resonator with metal nano-antenna for heat-assisted magnetic recording

Heat-assisted magnetic recording (HAMR) is a promising technology for achieving more than 10 Tbit/inch 2 recording density. A near-field transducer (NFT), which forms a small light spot on a recording medium, is necessary in HAMR. However, the heat generated by the NFT would melt the NFT itself. To solve this problem, the authors have proposed a novel device, in which a metal nano-antenna is attached to a semiconductor ring resonator. In this paper, the near-field light generated by this device was analyzed through a numerical simulation based on a 3-dimensional model including the recording medium to optimize the structure of the device. It was found that how to excite a desired eigenmode selectively among some eigenmodes is important to make the device effective. A light spot with a diameter of about 25 nm, which corresponds to the recording density of 1 Tb/inch 2 , was obtained on the surface of the recording medium. It was also found that the design parameters of the device must be optimized considering the recording medium.