Related Experiment Video
Updated: Jun 13, 2026
14:16
Fluorescence detection methods for microfluidic droplet platforms
Published on: December 10, 2011
Fluorescence modeling of droplets intersecting a focused laser beam
Bruno Frackowiak1, Cameron Tropea
1Institute for Fluid Mechanics and Aerodynamics, Technische Universität Darmstadt, Petersenstrasse 30, 64287 Darmstadt, Germany. Bruno.Frackowiak@sla.tu-darmstadt.de
Optics Letters
|May 4, 2010
Summary
This study examines laser-induced fluorescence (LIF) signals from water droplets. The findings reveal a size-dependent signal, suggesting LIF scattering can measure droplet size and velocity.
Area of Science:
- Fluid Dynamics
- Optical Diagnostics
- Spectroscopy
Background:
- Laser-induced fluorescence (LIF) is a valuable technique for droplet characterization.
- Previous applications focused on droplet size or temperature.
- Advanced methods are needed for precise droplet analysis.
Purpose of the Study:
- To rigorously examine laser-induced fluorescence (LIF) signals from water droplets.
- To investigate the relationship between LIF signal and droplet size.
- To explore LIF scattering for droplet size and velocity measurements.
Main Methods:
- Utilizing a fluorescence model based on generalized Lorenz-Mie theory.
- Employing ray tracing methods for calculations.
- Simulating water droplets seeded with Rhodamine 6G passing through focused laser beams.
Main Results:
- A detailed parametric study of the LIF signal was performed.
- A clear size-dependent signal was observed as droplets traversed the laser beam(s).
- The study analyzed signals from single and dual focused laser beams.
Conclusions:
- The observed LIF signal features are indicative of droplet size.
- LIF scattering presents promising opportunities for individual droplet size and velocity measurements.
- This research advances optical diagnostic techniques for sprays.
Related Concept Videos
01:16Confocal Fluorescence Microscopy
Confocal microscopy is an advanced microscopic technique. The prime advantage of the confocal microscope over other microscopy techniques is its ability to block the out-of-focus light from the illuminated samples using pinholes. It is widely used with fluorescence optics to obtain high-resolution, sharp contrast images. Unlike optical microscopes, confocal microscopes use a focused beam of light laser to scan the entire sample surface at different z-planes. These microscopes are, therefore,...
01:37Super-resolution Fluorescence Microscopy
Super-resolution fluorescence microscopy (SRFM) provides a better resolution than conventional fluorescence microscopy by reducing the point spread function (PSF). PSF is the light intensity distribution from a point that causes it to appear blurred. Due to PSF, each fluorescing point appears bigger than its actual size, and it is the PSF interference of nearby fluorophores that causes the blurred image. Various approaches to achieving higher resolution through SRFM have recently been developed.
01:05Total Internal Reflection Fluorescence Microscopy
Total internal reflection fluorescence microscopy or TIRF is an advanced microscopic technique used to visualize fluorophores in samples close to a solid surface with a higher refractive index, such as a glass coverslip. TIRF only allows fluorophores in proximity to the solid surface to be excited. When light from a medium with a lower refractive index (such as air) hits the glass coverslip at a critical angle, the light undergoes total internal reflection stead of passing through the glass.