Single molecule fluorescence saturation spectroscopy

Rodolphe Jaffiol; Pascale Winckler

doi:10.1117/12.2037029

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4 March 2014 Single molecule fluorescence saturation spectroscopy

Rodolphe Jaffiol, Pascale Winckler

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Proceedings Volume 8950, Single Molecule Spectroscopy and Superresolution Imaging VII; 89500C (2014) https://doi.org/10.1117/12.2037029
Event: SPIE BiOS, 2014, San Francisco, California, United States

Abstract

Saturation spectroscopy is a powerful method to investigate photophysical parameters of single fluorescent molecules. Nevertheless, the impact of a gradual increase, over a broad range, of the laser excitation on the intramolecular dynamics is not completely understood, particularly concerning their fluorescence emission (the so-called brightness). As we have presented in a previous paper [1], we interpret the evolution of the brightness with the laser power by cascade absorption of two and three photons within a five-level molecular system. This multi-photon consecutive absorption leads us to reconsider the common expression of the saturation curve of fluorescent molecule. Furthermore, this multi-photon absorption process also affects the observation volume of microscope. So, in this paper we propose to interpret the size increase of the confocal observation volume according to simulations based upon two often used expressions of the Point Spread Functions (PSF) in fluorescence microscopy.

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Rodolphe Jaffiol and Pascale Winckler "Single molecule fluorescence saturation spectroscopy", Proc. SPIE 8950, Single Molecule Spectroscopy and Superresolution Imaging VII, 89500C (4 March 2014); https://doi.org/10.1117/12.2037029

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