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Recurrence and photon statistics in fluorescence fluctuation spectroscopy.
Gert Zumofen1, Johannes Hohlbein, Christian G Hübner
1Swiss Federal Institute of Technology, Physical Chemistry, CH-8093 Zurich, Switzerland.
Physical Review Letters
|February 9, 2005
Summary
We observed fluorescence fluctuations in nanoparticles as they diffused through a laser focus. The resulting on/off time distributions exhibit power-law behavior, explained by a proposed diffusion-reaction model.
Area of Science:
- Physical Chemistry
- Nanotechnology
- Fluorescence Spectroscopy
Background:
- Understanding nanoparticle behavior is crucial in various scientific fields.
- Fluorescence fluctuations provide insights into dynamic processes at the nanoscale.
Purpose of the Study:
- To analyze fluorescence fluctuations of nanoparticles during laser focus transit.
- To model the observed temporal distributions of fluorescence signals.
Main Methods:
- Utilizing fluorescence spectroscopy to monitor nanoparticles.
- Applying an intensity threshold to generate on/off time traces.
- Analyzing distribution functions of on and off times.
Main Results:
- Observed power-law distributions for on/off times over several orders of magnitude (t^-alpha, alpha ≈ 1.5-2).
- Identified crossover to exponential decays at longer timescales.
- Developed a diffusion-reaction equation to interpret experimental data.
Conclusions:
- The study elucidates nanoparticle diffusion dynamics through a laser focus.
- The proposed diffusion-reaction model successfully explains both diffusion-controlled recurrence and photon statistics.
- This work offers a framework for analyzing transient fluorescence signals from nanoscale objects.