Controlling the localization and migration of optical excitation

Andrews, D. L. and Bradshaw, D.S. (2012) Controlling the localization and migration of optical excitation. In: Proceedings of SPIE - The International Society for Optical Engineering. UNSPECIFIED. ISBN 9780819492838

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    Abstract

    In the nanoscale structure of a wide variety of material systems, a close juxtaposition of optically responsive components can lead to the absorption of light by one species producing fluorescence that is clearly attributable to another. The effect is generally evident in systems comprising two or more light-absorbing components (molecules, chromophores or quantum dots) with well-characterised fluorescence bands at similar, differentiable wavelengths. This enables the fluorescence associated with transferred energy to be discriminated against fluorescence from an initially excited component. The fundamental mechanism at the heart of the phenomenon, molecular (resonance) energy transfer, also operates in systems where the product of optical absorption is optical frequency up-conversion. In contrast to random media, structurally organised materials offer the possibility of pre-configured control over the delocalization of energy, through molecular energy transfer following optical excitation. The Förster mechanism that conveys energy between molecular-scale components is strongly sensitive to specific forms of correlation between the involved components, in terms of position, spectroscopic character, and orientation; one key factor is a spectroscopic gradient. Suitably designed materials offer a broad scope for the widespread exploitation of such features, in applications ranging from chemical and biological sensing to the detection of nanoscale motion or molecular conformations. Recently, attention has turned to the prospect of actively controlling the process of energy migration, for example by changing the relative efficiencies of fluorescence and molecular energy transfer. On application of static electric fields or off-resonant laser light - just two of the possibilities - each represents a means for achieving active control with ultrafast response, in suitably configured systems. As the principles are established and the theory is developed, a range of new possibilities for technical application is emerging. For example, applications can be envisaged for new forms of all-optical switching and transistor action. There is also interest in engaging with the interplay of optical excitation and local nanoscale force, exploiting local responses to changes in dispersion forces, accompanying molecular energy transfer.

    Item Type: Book Section
    Faculty \ School: ?? UEA ??
    Faculty of Science > School of Chemistry
    University of East Anglia > Faculty of Science > Research Groups > Physical and Analytical Chemistry
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    Depositing User: Pure Connector
    Date Deposited: 19 Nov 2014 12:42
    Last Modified: 25 Jul 2018 00:50
    URI: https://ueaeprints.uea.ac.uk/id/eprint/51112
    DOI: 10.1117/12.979786

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