Comment on the letter by Jakeman et al. 'Correlation of scaled photon-counting fluctuations'

Abstract

Jakeman et al. (see Abstr. A73542 of 1972) have presented a method for measuring the full photocount correlation function which might be called single channel scaling (SCS). The advantage of SCS is that it can be used in conjunction with a clipped correlator to measure directly the full photocount correlation rather than the clipped correlation function. The authors point out an equally simple way of performing the same measurement and finite sum by uniformly and sequentially clipping (USC) incoming photocounts. With this method one simply clips sequentially from some maximum clipping level k=l during each of l+1 sampling periods, then starts over again at k=l. In this way the uniformity of the sampling is automatically ensured and can therefore be used as a technique to test experimentally the clipping uniformity of SCS. They performed an extensive set of measurements using both SCS and USC over a wide range of scaling and sequential clipping levels and found both methods lead to exactly equivalent results.