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Proceedings Paper

Photon-counting phase-modulation fluorometer for lifetime measurements
Author(s): Tetsuo Iwata; Akio Hori; Takeshi Kamada
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Paper Abstract

We propose a phase-modulation fluorometer that is applicable to a very weak fluorescence intensity level. In order to counter the single-photon event situation, we have introduced a combination of a time-to-amplitude converter (TAC) and a pulse height analyzer (PHA) to the phase- modulation fluorometer, the combination of which is usually used in the single-photon correlation method to measure fluorescence decay waveforms by pulsed excitation. In the proposed fluorometer, a sinusoidal response waveform that is shifted in phase over the reference one is obtained statistically as a histogram in the PHA memory and then the fluorescence lifetime can be calculated by the same procedure as the conventional analog phase-modulation method. The excitation light source used was a current- modulated ultraviolet light-emitting diode (UV LED), whose center wavelength was 370 nm and its spectral bandwidth was 10 nm. Fluorescence lifetimes of 17.6 ns and 5.7 ns obtained for 10 ppb quinine sulfate in 0.1 N H2SO4 and for 10 ppb rhodamine 6G in ethanol, respectively, agreed well with those reported in the literature.

Paper Details

Date Published: 8 May 2001
PDF: 4 pages
Proc. SPIE 4416, Optical Engineering for Sensing and Nanotechnology (ICOSN 2001), (8 May 2001); doi: 10.1117/12.427004
Show Author Affiliations
Tetsuo Iwata, Univ. of Tokushima (Japan)
Akio Hori, Univ. of Tokushima (Japan)
Takeshi Kamada, Univ. of Tokushima (Japan)


Published in SPIE Proceedings Vol. 4416:
Optical Engineering for Sensing and Nanotechnology (ICOSN 2001)
Koichi Iwata, Editor(s)

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