For the past 30 years Raman spectroscopy has been widely used for numerous chemical research applications. Now, the new Timegated® Raman technology broadens the application range of Raman to biosciences, geosciences and many others where the fluorescence emission has hindered successful Raman analyses.
The Achilles’ heel of conventional Raman technology is photoluminescence (including fluorescence, phosphorescence etc.). Photoluminescence is a competing phenomenon with Raman scattering and it can overlap the whole Raman signal in the measured spectra making the identification or quantification of materials impossible.
With the new Timegated® technology, we can now achieve Real Fluorescence Rejection.
How do we do this?
The sub-nanosecond (100 ps) laser excitation source and a time-gated single photon counting array detector create a totally new type of spectrometer able to acquire Raman spectra with real fluorescence rejection. The system rejects the (delayed) fluorescence while capturing the instantaneous Raman scattering signal. It also enables the acquisition of time-resolved fluorescence spectra by sequentially sampling the emission pulses at different temporal positions. This approach simultaneously opens up two windows for material characterization and provides valuable new information in several different application fields.
Apart from molecular structure information from Raman spectra, Timegated® technology can be used for time resolved fluorescence spectroscopy applications to monitor molecular interactions and motions that occur in the picosecond-nanosecond range.
Figure 1. Time-resolved emission spectrum of an olive oil measured with a Timegated® device. The temporally short and spectrally multi-peaked Raman signal is clearly seen over the temporally and spectrally broad photoluminescence spectrum. In this figure, the origin of the Time axis has no fundamental physical significance (the values are actually just the settings of the electronic delay generator).