Publication No: 809PSearch all ORC publications    

A nanoparticle as a bit of optical memory

B.F.Soares*, M.V.Bashevoy, K.F.MacDonald, F.Jonsson, N.I.Zheludev

Abstract

We report on the experimental demonstration of bistable memory functionality in nanoparticles by engaging transformations between different structural phases with radically different dielectric properties. Functional nanoparticles acting, for example, as waveguiding or as switchjng structures are expected to play a very important role in future nanophotonic devices. In recent experiments with a single nanoparticle, we demonstrated that a nanoparticle with a diameter of several tens of nanometres exhibits equilibrium coexistences between a number of solid and disordered structural phases with very different dielectric properties. The coexistence can be controlled with only a few picojoules of external optical excitation in a highly reversible and reproducible fashion. In the present experiments, we show that by coding a low reflectivity phase as logical '0' and a high reflectivity phase as logical '1', an all-optical memory operating at very low powers can be achieved in gallium nanoparticles. The memory is written by a single optical pulse that irreversibly switches nanoparticles from state '0' to state '1', while it can then be erased by cooling the nanoparticles down, for example by switching off an auxiliary laser. Therefore, our results show for the first time that a resonator-less optical memory element can be created with a nanoparticle undergoing a structural transformation.


QEP-17 at Photon06 Manchester, UK 4 - 7 Sep (2006)

Publisher′s URL: Only abstract is available

Southampton ePrint id: 57751

 

 

 

Copyright University of Southampton 2006