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A phase-shift fluorometer using a laser and a transverse electrooptic modulator for subnanosecond lifetime
Biophysical Journal
|December 1, 1977
Summary
This study presents a simple phase-shift fluorometer utilizing continuous laser excitation and a low-voltage electrooptic modulator. This design simplifies fluorescence measurements and allows for accurate phase determination using modulated Raman and Rayleigh scattering.
Area of Science:
- Analytical Chemistry
- Spectroscopy
- Instrumentation
Background:
- Phase-shift fluorometry is a powerful technique for studying molecular dynamics.
- Traditional fluorometers often require high-voltage modulators, limiting their practicality.
- Continuous laser excitation offers advantages for modulated measurements.
Purpose of the Study:
- To describe a simple and efficient phase-shift fluorometer.
- To demonstrate the utility of a low-voltage transverse mode electrooptic modulator.
- To establish a reliable method for determining the zero reference phase in fluorescence measurements.
Main Methods:
- Utilized continuous laser excitation with a transverse mode electrooptic modulator (200 V, up to 100 MHz).
- Detected modulated fluorescence signals using a photomultiplier tube and a radio frequency (RF) tuned amplifier.
- Determined RF phase via phase-sensitive detection with a double balanced mixer and a PIN photodiode reference.
Main Results:
- Successfully implemented a phase-shift fluorometer with a low-voltage modulator.
- Observed modulated Raman solvent and Rayleigh scattering signals.
- Demonstrated the convenience of these scattering signals for determining the zero reference phase.
Conclusions:
- The developed phase-shift fluorometer is simple, efficient, and practical.
- The use of a low-voltage modulator enhances accessibility and ease of use.
- The method provides accurate phase determination, crucial for fluorescence lifetime studies.