New magnetic crystal to harness light
doi:10.1038/nindia.2011.55 Published online 25 April 2011
Researchers have captured light within the confines of a new nanosized crystal made from a nanosized perforated gold layer laid on a ferromagnetic film. This technique allows light to be localized at length scales much shorter than its wavelength, which is good news for the nanoscale integration of photonics and electronics.
Conventional wisdom tells us that light can only be controlled at length scales down to a few hundred nanometres — the usual resolution limit of optical microscopes and telescopes. The inability to manipulate light at length scales of a few nanometres (and lower) limits the applications of nanotechnology.
Plasmonics allows light to be controlled on length scales much shorter than its wavelength, and can therefore be used to harness the subwavelength applications of nanotechnology. Such control requires the use of good metallic crystals that exhibit interesting magneto-optical effects.
Researchers have traditionally constructed magneto-optical materials from ferromagnetic metals that have high optical losses. To reduce optical loss in such materials, the researchers designed a magnetoplasmonic crystal — a new magneto-optical material — comprising a nanostructured perforated gold metal film on top of a ferromagnetic dielectric (bismuth iron garnet film) smeared on a non-magnetic substrate (gadolinium gallium garnet substrate).
The researchers carried out experiments in which the crystal was simultaneously exposed to light and high external magnetic fields. The crystal exhibited low optical loss, giving it a wide range of applications for biosensors, magnetic field sensors and magnetic read heads. The researchers say that such crystals might also have applications in all-optical magnetic data storage devices that operate at terahertz frequencies.
The authors of this work are from: A. M.Prokhorov General Physics Institute, V. A. Kotelnikov Institute of Radio Engineering and Electronics, Russian Academy of Sciences, and M. V. Lomonosov Moscow State University, Moscow and A. F. Ioffe Physical-Technical Institute, Russian Academy of Sciences, St Petersburg, Russia, Experimentelle Physik, Technische Universität Dortmund, Dortmund, Germany, and Tata Institute of Fundamental Research, Mumbai, India.
- Belotelov, I. V. et al. Enhanced magneto-optical effects in magnetoplasmonic crystals. Nature Nanotechnology. doi: 10.1038/nnano.2011.54 (2011)