Planar laser-induced fluorescence

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A simplified PLIF experimental facility.
A simplified PLIF experimental facility.

Planar laser-induced fluorescence (PLIF) is an optical diagnostic technique widely used for flow visualization and quantitative measurements. PLIF has been shown to be used for velocity, concentration, temperature and pressure measurements.

Contents

[edit] Working

A typical PLIF setup consists a source of light (usually a laser), an arrangement of lenses to form a sheet, fluorescent medium, collection optics and a detector. The light from the source, illuminates the medium, which then fluoresces. This signal is captured by the detector and can be related to the various properties of the medium.

The typical lasers used as light sources are pulsed, which provide a higher peak power than the continuous-wave lasers. Also the short pulse time is useful for good temporal resolution. Some of the widely used laser sources are Nd:YAG laser, dye lasers, excimer lasers, and ion lasers. The light from the laser (usually a beam) is passed through a set of lenses and/or mirrors to form a sheet, which is then used to illuminate the medium. This medium is either made up of fluorescent material or can be seeded with a fluorescent substance. The signal is usually captured by a CCD or CMOS camera (sometimes intensified cameras are also used). Timing electronics is often used to synchronize pulsed light sources with intensified cameras.

[edit] Basic principles

An electron in the lower (ground) energy level (1) absorbs a photon and is transferred to the higher (excited) energy level (2). This electron then emits a photon while returning to the lower energy level (3), which is seen as fluorescence signal.
An electron in the lower (ground) energy level (1) absorbs a photon and is transferred to the higher (excited) energy level (2). This electron then emits a photon while returning to the lower energy level (3), which is seen as fluorescence signal.

[edit] Comparision with other techniques

[edit] Advantages

- Able to obtain velocity concentrations when combined with particle image velocimetry technique.

[edit] Disadvantages

[edit] Applications

[edit] References

  • Seitzman, J. M.; Hanson, R. K. (1993). "Planar Fluorescence Imaging in Gases", in Taylor, A. M. K. P.: Instrumentation for Flows with Combustion. Academic Press, pp. 405-466. ISBN 0-12-683920-4. 

[edit] See also

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