| Heat Assisted Magnetic Recording (HAMR) is a method that allows for storage of data on a magnetic recording medium at greater densities than are currently seen (with a goal of TB/in2 and beyond). To this end, near field transducers (NFTs) need to be able to efficiently focus light to very small spots (and hence provide very small thermal spots), all with reasonable efficiency, to produce a practical HAMR system. The near field transducers we investigate are surface plasmon metal optical waveguides (subwavelength sized). In this document we examine several NFT topologies that may be promising for HAMR. Additionally we investigate the role of surface roughness on the propagation of surface plasmons along a HAMR NFT. Finally, we are investigating a novel type of light delivery system for HAMR that uses cavity modes of dielectric resonators (driven internally by quantum dots that absorb incoming light, and then emit a wavelength that couples strongly to the dielectric disks's resonant mode. In all cases, the figures of merit that are used to determine the suitability for a given NFT for HAMR applications are the optical spot size and the efficiency of the optical power delivered to the medium. We especially seek to quantify the amount of power coupled from the air bearing surface end of the NFTs across the air gap and into the medium. In all cases we aspire to spot sizes on the order of a few 10s of nm and efficiencies (optical input to medium heating) of greater than 5%. We show in this document that several NFT configurations are more promising than others, and indicate future research directions that are promising based on the results herein. |
