New light sources for time correlated single photon counting in commercially available spectrometers

摘要

The method of Time Correlated Single Photon Counting requires high repetitive light sources (>100kHz) with pulse widths of ideally less than approximately 20ps. While these light sources have been available for some time now in the form of Ti:Sapphire lasers, picosecond pulsed diode lasers (<90ps) and light emitting diodes ( < 700ps), they all have the drawback of either having no spectral tunability, or tunability over a very narrow spectral range (10nm-100nm). 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 Time Correlated Single Photon Counting. 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 500nm.