Which light sources are most suitable for fluorescence lifetime measurement and imaging?
The answer to this question depends on many factors such as the lifetime and spectral excitation ranges of interest, budget, required stability levels, size and weight considerations etc. A brief and necessarily incomplete summary is as follows: Xenon flashlamps For long lifetime samples (>20 microseconds or so) a fast pulsed Xenon flashlamp is a good compact light source. This gives output from UV to IR and is intense, compact and relatively inexpensive. Some flashlamps suffer from significant ‘afterglow’, particularly at longer wavelengths and this aspects needs to be investigated for each application. Xenon flashlamps are typically pulsed at several hundred Hz with microsecond pulse widths. Faster flashlamps with sub-microsecond pulse widths are available commercially for special applications. Nanosecond pulsed Xenon flashlamps have also been described in the literature (see Iwata, I. et al. Rev. Sci. Instrumen. 71(11), 4045-49, (2000)). Nitrogen/Dye lasers Nitrogen lasers and dye l
