2. Time Correlated Single Photon Counting (TC-SPC)
The method is based on the detection of single photons and the construction of a histogram of their arrival times with respect to a reference signal, usually the laser pulse used for excitation. As a statistical method it requires a high repetition rate excitation source to accumulate a sufficient number of photon events for a required precision of the recovered decay data. The TCS-PC technique outperforms all other techniques in sensitivity, dynamic range, data accuracy and precision. It has furthermore the advantage that a low intensity light source is used. The parameters of multi-exponential and several non-exponential decay laws can be recovered by iterative convolution.
Millenia Pro 10W, Tsunami, Pulse Picker, Second and Third Harmonic Generation, (Spectra-Physics), one detection scheme based on MCP-PMT Hamamatsu, TC-SPC electronics.
The most accurate method to measure fluorescence decays. The time domain covers the decay times of most natural and synthetic samples. The time resolution is limited to 40 ps while the excitation and detection range spread over a range from 260 to 900 nm.