Gigahertz frequency-domain fluorometry: Applications to picosecond processes and future developments

Joseph R. Lakowicz, Gabor Laczko, Ignacy Gryczynski, Henryk Cherek, Wieslaw Wiczk

Research output: Contribution to journalArticle

3 Scopus citations

Abstract

We describe our frequency-domain fluorometer which allows phase angle and demodulation measurements from 8 MHz to 2 GHz. This instrument using the harmonic content of a 7.59 MHz train of 5 ps pulses as the modulated excitation source. The detector is a microchannel plate PMT (R1564U), whose bandwidth extends to 2 GHz. Using this instrument we examined rapid rotational motions of indole in low viscosity solvents. To date, the shortest correlation time we have determined was 7 ps, for indole in methanol at 80°C. For indole in cyclohexane at 20°C we were able to resolve two rotational correlation times of 17 and 73 ps. It now appears that the frequency range can be extended to 8 GHz, so still faster processes should be observable.

Original languageEnglish
Pages (from-to)15-22
Number of pages8
JournalProceedings of SPIE - The International Society for Optical Engineering
Volume909
DOIs
StatePublished - 24 Jun 1988

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