New Light Sources for Time-Correlated Single Photon Counting in Commercially Available Spectrometers
The method of Time-Correlated Single Photon Counting (TCSPC) requires high repetitive light sources (>100 kHz) with pulse widths of ideally less than approximately 20 ps. While these light sources have been available for some time now in the form of Ti:Sapphire lasers, picosecond pulsed diode lasers (<90 ps) and light emitting diodes (<700 ps), they all have the drawback of either having no spectral tunability, or tunability over a very narrow spectral range (10 nm – 100 nm). While this is often sufficient for specific laboratory setups for measurements of fluorescence lifetimes, commercial Fluorescence Lifetime Spectrometers have suffered for a long time from the lack of the availability of simple, compact and relatively inexpensive broad spectral band light sources that can be employed for TCSPC. A new light source as an integral part of a commercial fluorescence lifetime spectrometer will be discussed that allows tunability over a wide spectral band of more than 500 nm.