The fast development of nanoscience, especially in the field of nanoelectronics, nanophotonics and plasmonics, has shown a great demand for new nanofabrication techniques to fulfil diverse requirements. The nanolithographic methods, e.g conventional photolithography, focused electron beams lithography (EBL), and focus ion beams (FIB), all exhibit the capability for nanostructure fabrication but most of them inherently suffer from their nature, which limit the size of nanostructures, fabrication area, and throughput at reasonable costs. The limitations of these conventional lithographic techniques have motivated the development of alternative approaches such as micro-contact printing, scanning probe lithography and nanoimprinting lithography (NIL). In this paper, we propose a new alternative laser based approach which could satisfy the requirements of high resolution, fast processing speed for large area fabrication of sub-wavelength nanohole and nanoparticle arrays with feature size controllably varied from a few tens to a few hundreds nanometers. The technique, named as plasmonic nanoparticle lithography, effectively combines the laser induced transfer (LIT) [1, 2] and light-induced near-field nanomodification [3, 4] relying on the optical enhancement and thermal effect in near-field under spherical plasmonic nanoparticles. It allows producing ordered sub-wavelength nanohole arrays in a thin mask layer (e.g. Chromium film) upon laser exposure. Subsequent post-processing allows transferring the nanohole array into a desired substrate or converting it into an array of pillars made out of a desired material.
1. A. I. Kuznetsov, A. B. Evlyukhin, M. R. Gonçalves, C. Reinhardt, A. Koroleva, M. L. Arnedillo, R. Kiyan, O. Marti, and B. N. Chichkov, “Laser fabrication of large-scale nanoparticle arrays for sensing applications”, ACS Nano., 5(6),4843-9 (2011).
2. A. I. Kuznetsov, R. Kiyan, and B. N. Chichkov, "Laser fabrication of 2D and 3D metal nanoparticle structures and arrays", Optics Express, 18(20), 21198-21203 (2010).
3. P. G. Kika, S. A. Maiera and H. A. Atwater, Plasmon Printing - a New Approach to Near-Field Lithography, 2001 MRS Fall Meeting, MRS Proceedings, Volume 705 (2001).
4. A. Plech, V. Kotaidis, M. Lorenc and J. Boneberg, “Femtosecond laser near-field ablation from gold nanoparticles”, Nature Physics, 2, 44- 47 (2006).
In this work, effective magnetic fields relevant to all-optical magnetic recording (AOMR) are analyzed considering,
specifically, optically-induced spin-orbit (OSO) coupling and the Inverse Faraday Effect. Computing these fields
with reasonable estimations of the required parameters, it is shown that OSO fields developed in typical rare earth
alloys have a distribution with exterior rings of maximum amplitude in the perpendicular component, in contrast to
the IFE field which has its maximum in the center. These observations may correlate to experimental observations
that have revealed exterior rings in the recorded spots during the AOMR process.
This work presents a thermal analysis that explains experimental observation in all-optical magnetic recording (AOMR).
An integrated model is used to describe thermal processes at different time scales in AOMR. The formation of magnetic
marks is discussed and implemented by developing a simulator based on 3-dimensional finite element method (FEM).
The simulator is able to carry out thermal analysis of the thin film media and is a useful tool for design of AOMR media
structure, especially for the thermal sink layer.
In heat assisted magnetic recording, near field optical transducer is a key component for its success. Due to the near field
properties, the transducer design has to be done combining with media. FePt is a potential recording material for heat
assisted recording. In this paper, the measured optical constant of FePt thin film was introduced, and the design and
simulation of c-aperture transducer with FePt media for multiple Tb/in2 heat assisted magnetic recording application
were performed. The light spot sizes of around 15nm with high efficiency were obtained. Optical transducer is used to
heat the media locally. Its final target is to generate smaller thermal profile to meet the requirement of recording density.
Therefore, using obtained beam spot as heat source, thermal simulations were carried out with media material's thermal
parameters. The simulation results show that recording density of 3Tb/in2 is possible.