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Updated: Jan 1, 2026

Fluorescence detection methods for microfluidic droplet platforms

Fluorescence detection methods for microfluidic droplet platforms

Published on: December 10, 2011

Phase Fluorometry Using a Continuously Modulated Laser Diode.

Richard B Thompson¹, Joan K Frisoli¹, Joseph R Lakowicz¹

¹University of Maryland School of Medicine, Department of Biological Chemistry and Center for Fluorescence Spectroscopy, 660 West Redwood Street, Baltimore, Maryland 21201.

Analytical Chemistry

|December 17, 2019

Summary

This summary is machine-generated.

This study demonstrates phase fluorometric measurements using amplitude-modulated laser diodes for determining fluorescence lifetimes of cyanine dyes. Higher radio frequency power improved modulation but risked light output distortion.

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Area of Science:

Optics and Photonics
Photochemistry
Laser Spectroscopy

Background:

Phase fluorometry is a technique for measuring fluorescence lifetimes.
Laser diodes offer a compact and efficient excitation source for fluorescence measurements.
Cyanine dyes are widely used in various applications due to their photophysical properties.

Purpose of the Study:

To investigate the use of directly amplitude-modulated laser diodes for phase fluorometric measurements.
To determine the fluorescence lifetimes of common cyanine laser dyes.
To analyze the effect of radio frequency power on diode modulation and light output.

Main Methods:

Utilized 670-nm and 791-nm laser diodes as excitation sources.
Employed a commercial phase fluorometer for fluorescence lifetime measurements.
Investigated the influence of radio frequency (RF) power and direct current (DC) on laser diode modulation.

Main Results:

Measured fluorescence lifetimes for cyanine dyes ranging from 220 picoseconds (ps) to 1.7 nanoseconds (ns).
Observed that increased DC current necessitated higher RF power for comparable modulation.
Identified distortion in laser light output at excessive RF power levels.

Conclusions:

Directly amplitude-modulated laser diodes are suitable for phase fluorometry of cyanine dyes.
Optimizing RF power is crucial to balance modulation depth and avoid output distortion.
The study provides valuable data on fluorescence lifetimes for specific cyanine dyes.