Burst-Integrated Fluorescence

Burst-Integrated Fluorescence Lifetime (BIFL) Experiments... 

BIFL burst integrated fluorescence lifetime DRIFT diffuse-reflectance infrared Fourier transform... 

Spectroscopy of single molecules is based on fluorescence correlation, photoncounting histograms, or burst-integrated-lifetime techniques. Each case requires recording not only the times of the photons in the laser period, but also their absolute time. Modem time-resolved single molecule techniques therefore use almost exclusively the FIFO (time-tag) mode of TCSPC. The FIFO mode records all information about each individual photon, i.e. the time in the laser pulse sequence (micro time), the time from the start of the experiment (macro time), and the number of the detector that detected the photon (see Sect. 3.6, page 43). 

Figure 18-15 Tracks of two molecules of 20 pM rhodamine 6G in silica gel observed by fluorescence integrated over 0.20-s periods at 0.78-s intervals. Some points are not connected, because the molecule disappeared above or below the focal plane in the 0.45-ixnrvthick film and was not observed in a particular observation interval. In the nine periods when molecule A was in one location, it might have been adsorbed to a particle of silica. An individual molecule emits thousands of photons in 0.2 s as the molecule cycles between ground and excited states. Only a fraction of these photons reaches the detector, which generates a burst of —10-50 electrons. [From K. s. McCain, D. C. Hanley, andJ. M. Harris. "Single-Molecule Fluorescence Trajectories tor Investigating Molecular Transport in Thin Silica Sol-Gel Films," Anal.

---