Plasmonic near-field transducer for heat-assisted magnetic recording

Abstract

Plasmonic devices, made of apertures or antennas, have played significant roles in advancing the fields of optics and opto-electronics by offering subwavelength manipulation of light in the visible and near infrared frequencies. The development of heat-assisted magnetic recording (HAMR) opens up a new application of plasmonic nanostructures, where they act as near field transducers (NFTs) to locally and temporally heat a sub-diffractionlimited region in the recording medium above its Curie temperature to reduce the magnetic coercivity. This allows use of very small grain volume in the medium while still maintaining data thermal stability, and increasing storage density in the next generation hard disk drives (HDDs). In this paper, we review different plasmonic NFT designs that are promising to be applied in HAMR. We focus on the mechanisms contributing to the coupling and confinement of optical energy. We also illustrate the self-heating issue in NFT materials associated with the generation of a confined optical spot, which could result in degradation of performance and failure of components. The possibility of using alternative plasmonic materials will be discussed.

Colloidal Plasmonic Titanium Nitride Nanoparticles: Properties and Applications

“…The high melting point and hardness of the material enables the use of plasmonic effects for applications where tough operational conditions are required [13,14,19,20]. Heat assisted magnetic recording [21], solar/thermophotovoltaics [22], plasmon enhanced photocatalysis [23][24][25], and plasmon assisted chemical vapor deposition [26] are some of the applications that could take advantage of durable plasmonic TiN nanostructures. TiN is a chemically inert material widely used in CMOS and biomedical devices [5,[27][28][29][30].…”

Optical and thermal analysis of the light-heat conversion process employing an antenna-based hybrid plasmonic waveguide for HAMR

“…Altogether, the addition of a heat spreader and the optimization process may be applied to antenna-based structures composed of other materials along with slight modifications. The optical and thermal efficiencies for the design either met or surpassed current industry standards for antenna-based NFTs with potential to be improved upon given optimization of the magnetic write pole or media [3,4,22,25,48]. …”

“…Optimization of the taper length according to plasmon wavelength is fundamentally different than optimization via coupling length such as that seen in similar antenna-based NFTs proposed for HAMR and may extend the taper length by many microns making a less compact design [16,46]. A maximum optical absorption efficiency around 8.5% is obtained for L taper = 330 nm comparing well with other HAMR devices [1,22,25,38,47,48]. Though the back reflection into the Si waveguide is nearing a maximum at this point, further alterations can be made by abutting anti-reflective coatings or anti-reflective trenches which have been shown capable of improving optical efficiencies significantly in plasmonic NFTs [49].…”

Plasmonic nanoantenna design and fabrication based on evolutionary optimization

“…For example the occurrence of plasmon resonances [4] and volume currents [5] have to be considered, and new phenomena become important, e.g. the kinetic inductance [6] and Ohmic loss [7]. To rescue the concepts of radio frequency antenna technology into the optical realm the principle of effective wavelength scaling was introduced [8] and applied to e.g.…”