Optoelectronic closed loop auto-oscillator for fluorescence lifetime detection: A new fluorimetry technique with applications to chemical/biosensors

Journal Article

We present a new approach to excited state fluorescence lifetime-based measurements which is inexpensive and highly sensitive. The detection system consists of a closed-loop optoelectronic arrangement containing an intermediate frequency resonance amplifier, a fluorescence excitation light source (for example, a light emitting diode or a semiconductor laser), a fiber optic delay line, and a photodetector. The system exhibits self-oscillations in the vicinity of the frequency Ω∼l/τ (where τ is the excited state lifetime) which manifest themselves as modulation of the light. Changes in the excited state lifetime alter the phase delay of the loop, which in turn causes a frequency shift in the modulation signal. The frequency shift can be measured very precisely with a frequency counter. With appropriate averaging, this technique can yield subpicosecond resolution of shifts in lifetime. This technique is suited for chemical/biological sensing applications, and can be easily duplicated for chemical/biological sensor arrays.

Full Text

Duke Authors

Cited Authors

  • II, MJO; Rabinovich, E; Svimonishvilli, T; Brueck, SRJ; Lopez, GP

Published Date

  • 2001

Published In

  • Proceedings of SPIE - The International Society for Optical Engineering

Volume / Issue

  • 4263 /

Start / End Page

  • 170 - 177

Digital Object Identifier (DOI)

  • 10.1117/12.429336