Objective
1. To search for enhancement of Raman scattering due to effect of photon density of states on model periodic dielectric nanostructures and to compare the effect of photon density of states in Raman scattering and luminescence of molecules and semiconductor nanocrystals (quantum dots) on periodic nanostructures;
2. To establish correlations or anti-correlations in spontaneous emission and Raman scattering of light by molecules and semiconductor nanocrystals adsorbed on periodic metal-dielectric nanostructures exhibiting strong surface enhanced Raman scattering.
Spontaneous Raman scattering of light is basically a result of interaction of a virtually excited molecule (or nanoparticle, quantum dot) with electromagnetic vacuum. Therefore in nanostructures where spatial variation of dielectric function results in spectral redistribution of photon density of states (DOS), a modification of spontaneous scattering rate by a virtually excited quantum system may occur. However, the effect of modified photon DOS in nanostructures on Raman scattering has not been recognised to date and not systematically examined in experiments. Thus there is a definite gap in the knowledge of how photons are spontaneously scattered by a quantum system under condition of spectral and spatial redistribution of photon DOS in mesoscopic structures. It is the purpose of the project to verify a prediction made by the authors of the project of the noticeable effect of photon density of states on Raman scattering using model periodic nanostructures (so called photonic crystals) combined with molecular and nanocrystalline probes. In case of successful experiments, the effect can be used for Raman scattering enhancement in purely dielectric structures without non-desirable chemical interactions and charge transfer properties inherent in metal nanostructures.
Periodic metal-dielectric nanostructures are known to be extremely efficient in surface enhancement of Raman scattering (SERS) of adsorbed molecules. In the project, colloidal dielectric crystals previously proposed as prototype structures for photonic crystals in the visible are considered as promising SERS-active substrates when covered with thin films of coinage metals. Using these substrates surface enhanced Raman scattering as well as surface enhanced luminescence, which is very interesting, but less understood physical phenomenon would be systematically studied. Parallel research with nanocrystals and molecules as probes will be performed providing valuable insight to mechanisms of surface enhanced scattering and emission of light. For the first time surface enhancement of Raman scattering and luminescence by nanocrystals will be examined which is important in the context of their application as efficient photostable fluorescence probes.
The proposed tasks feature an interdisciplinary character lying between spectroscopy, quantum optics, solid state physics, physical chemistry, molecular physics, colloidal science. The potential applications can be foreseen in chemistry (ultrasensitive analysis), biology (high-resolution cell research with fluorescent labelling including possible DNA sequencing), and medicine (monitoring of drug interaction with tissues and cells).
The Consortium includes 5 teams from different institutions with high-quality specialists in complementary fields headed by:
Professor U. Woggon - Physics Department, University of Dortmund, Germany;
Professor A. Meijerink - Debye Institute, University of Utrecht, The Netherlands;
Dr S. Gaponenko - Inst. Molecular and Atomic Physics, National Academy of Sciences, Minsk, Belarus;
Professor S. Maskevich - Dept. of Physics and Technology, Grodno State University, Grodno, Belarus;
Dr A. Fedorov- Vavilov State Optical Institute, St-Petersburg, Russia.
Call for proposal
Data not availableFunding Scheme
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44227 Dortmund
Germany