Photon counting, single, time-correlate

When the experimental system emits light after the initial pumping pulse, quite different techniques can be used to obtain a time-resolved spectrum of the sample emission. The simplest of these is time-correlated single photon counting. The time resolution of this technique is limited by the design of the photon detectors. Two other methods used in emission spectroscopy are the streak camera and... 

The other coimnon way of measuring nanosecond lifetimes is the time-correlated single-photon counting... 

O Conner D V and Phillips D 1984 Time-Correlated Single Photon Counting (London Academic)... 

Figure C1.5.12.(A) Fluorescence decay of a single molecule of cresyl violet on an indium tin oxide (ITO) surface measured by time-correlated single photon counting. The solid line is tire fitted decay, a single exponential of 480 5 ps convolved witli tire instmment response function of 160 ps fwiim. The decay, which is considerably faster tlian tire natural fluorescence lifetime of cresyl violet, is due to electron transfer from tire excited cresyl violet (D ) to tire conduction band or energetically accessible surface electronic states of ITO. (B) Distribution of lifetimes for 40 different single molecules showing a broad distribution of electron transfer rates. Reprinted witli pennission from Lu andXie [1381. Copyright 1997 American Chemical Society.

Figure 4.6 shows an apparatus for the fluorescence depolarization measurement. The linearly polarized excitation pulse from a mode-locked Ti-Sapphire laser illuminated a polymer brush sample through a microscope objective. The fluorescence from a specimen was collected by the same objective and input to a polarizing beam splitter to detect 7 and I by photomultipliers (PMTs). The photon signal from the PMT was fed to a time-correlated single photon counting electronics to obtain the time profiles of 7 and I simultaneously. The experimental data of the fluorescence anisotropy was fitted to a double exponential function. 

Gompf B, Gunther R, Nick G, Pecha R, Eisenmenger W (1997) Resolving sonoluminescence pulse width with time-correlated single photon counting. Phys Rev Lett 79 1405-1408... 

Advanced Time-Correlated Single Photon Counting Techniques... 

Becker, W., Bergmann, A., Hink, M. A., Konig, K., Benndorf, K. and Biskup, C. (2004b). Fluorescence lifetime imaging by time-correlated single-photon counting. Microsc. Res. Tech. 63, 58-66. 

O Connor, D. V. and Phillips, D. (1984). Time-Correlated Single Photon Counting. Academic press, London. 

Becker, W. (2005). Advanced time-correlated single photon counting techniques. Springer, Berlin Heidelberg New York. 

The introduction and diversification of genetically encoded fluorescent proteins (FPs) [1] and the expansion of available biological fluorophores have propelled biomedical fluorescent imaging forward into new era of development [2], Particular excitement surrounds the advances in microscopy, for example, inexpensive time-correlated single photon counting (TCSPC) cards for desktop computers that do away with the need for expensive and complex racks of equipment and compact infrared femtosecond pulse length semiconductor lasers, like the Mai Tai, mode locked titanium sapphire laser from Spectra physics, or the similar Chameleon manufactured by Coherent, Inc., that enable multiphoton excitation. 

Understand the principles of time-correlated single-photon counting. 

The technique of time-correlated single-photon counting (Figure 3.4) is used to measure an excited singlet-state lifetime, x. The sample is irradiated with a very short-duration light pulse ( lns) to ensure any given molecule will only be excited once during the pulse. As soon as... 

Figure 3.4 Schematic diagram of the principal components of a time-correlated single-photon counting apparatus...

D. J. S. Birch and R. E. Imhof, Time-domain fluorescence spectroscopy using time-correlated single-photon counting, in Topics in Fluorescence Spectroscopy (J. R. Lakowicz, ed.), Vol. 1, pp. 1-95, Plenum Press, New York (1991). 

From the standpoint of time domain (e.g., time-correlated single photon counting) experiments the method of modelocking is not too crucial as long as the pulse jitter is modest (some picoseconds), and the pulse intensity doesn t vary too much if the time-to-amplitude converter is being started instead of stopped by the excitation pulse, it may be immaterial. From the standpoint of the frequency domain, however, the... 

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