Time-resolved single photon counting

For fluorescence decay curves of the J-aggregate LB films of [CI-MC] mixed with various matrix agents, measured with a picosecond time-resolved single photon counting system, three components of the the lifetimes fitting to exponential terms in the following equation ... 

The decay of phosphorescence emissions can be observed easily with conventional flash photolysis instruments, since they last between ms and seconds. However, fluorescence lifetimes are of the order of ns and such kinetics can be measured only by laser flash photolysis or by time-resolved single photon counting. 

Fluorescence Picosecond Time-Resolved Single Photon Counting... 

Figure 12. Set-up for direct NIR luminescence measurements in vitro and in vivo, using a high-sensitivity photomultiplier tube and time-resolved single-photon counting. The O2 is produced by a short-pulse laser. The diffusely scattered light from the tissue is rejected by a filter and then the luminescence signal and background around 1270 nm are then sampled using a set of narrow band-pass filters.

Cr=crystal Sm=smectic CrSmB = crystal smectic B N=nematic Ch=cholesteric I=isotropic fluorescence = steady state fluorescence SPC = time-resolved single photon counting CPF=circularly polarized fluorescence UV-vis = UV-visible absorption spectrophotometry DSC=differential scanning calorimetry OM = optical microscopy XRD = X-ray diffraction EPR=electron paramagnetic resonance NMR=nuclear magnetic resonance. 

The existence of an additional neutral state absorbing at almost the same wavelength as A was previously proposed on the basis of time-resolved single-photon counting spectroscopy, although a role was not assigned to this state in the dark dynamics. 

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