Time-Resolved Fluorescence Spectroscopy – TCSPC

Researchers at the Guldi Laboratory at the Friedrich-Alexander University Erlangen used the SuperK EXTREME with a built-in pulse picker, in combination with the spectral filter SuperK VARIA and a Fluorolog System (Horiba Scientific) to determine lifetimes of photoexcited states.

Green spectroscopy

Their research revolves around the probing of photochemical and photophysical processes as these play a major role in energy and/or electron transfer reactions. These processes are of importance for the future as they govern the basis for applications in energy conversion and storage.

Time-Correlated Single Photon Counting (TCSPC) is a widely used technique to gather insights into fluorescence lifetimes on the ps and ns timescale. To study different molecular building blocks and materials, a short-pulse excitation source with high, but variable repetition rates, and an adjustable excitation wavelength in the visible and near-infrared (420-840 nm) is required.

To perform their research the group has an experimental setup as depicted below.

Professor Dirk M. Guldi and his team use a SuperK EXTREME EXB-6 white light laser and a SuperK VARIA filter box to match the absorption wavelength of the material examined.  If necessary, the pulse picker reduces the repetition rate as a means to secure sufficient time for the photoexcited materials to reach their ground state before the next photoexcitation-fluorescence cycle is initiated.

NKT’s Supercontinuum laser with the built-in pulse picker in combination with the VARIA is an extremely useful excitation source for TCSPC experiments. Due to its flexibility, it replaces several alternative lasers, which typically provide only one wavelength at a certain repetition rate. Besides being a costly very attractive alternative (especially if several excitation wavelengths are needed) using a supercontinuum laser eliminates time-consuming hardware modifications and alignments that occur while switching excitation sources. The laser operation is straightforward. Its control can easily be implemented directly in the Fluorolog Software. We have been using the SuperK EXTREME with pulse picker and the SuperK VARIA very successfully for more than a year without any troubles.

Prof. Dr. Dirk M. Guldi, FAU Erlangen