Regensburg 2010 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 12: Poster: Electronic and Optical Properties of Organic Systems

CPP 12.2: Poster

Monday, March 22, 2010, 16:30–18:00, Poster C

Frequency-Domain FLIM Measurements of Fluorophore Mixtures with a Custom-Built Low-Cost Setup — •Thomas Bezold and Lothar Kador — University of Bayreuth, Institute of Physics and Bayreuther Institut für Makromolekülforschung (BIMF), 95440 Bayreuth, Germany

Fluorescence lifetime imaging microscopy (FLIM) in the frequency domain is applied to different binary mixtures of fluorophores. The custom-built setup is based on a confocal microscope and employs standard communications-type radiofrequency electronics. Excitation is performed with a cw laser which is amplitude-modulated with an acousto-optic modulator (AOM). Modulation frequencies between 25 and 50 MHz are generated with a computer-controlled direct digital synthesizer (DDS). The fluorescence signal of the sample is demodulated at the fixed frequency of 70 MHz with an I-Q demodulator. Its modulation amplitude and phase shift with respect to the excitation yield information about the fluorescence lifetime(s) in the sample. Single- and bi-exponential fluorescence decays are analysed with a polar-plot technique [1].

[1] G. I. Redford and R. M. Clegg, J. Fluor. 15, 805 (2005).