Intensity Temporal Autocorrelation (G2)

Definition: Intensity Temporal Autocorrelation (G_2) or its normalized form, “Normalized Intensity Temporal Autocorrelation (g_2)”, is the most commonly measured quantity in Diffuse Correlation Spectroscopy (DCS) measurements. Normalized Electric Field Autocorrelation function is often derived from g_2 using the so-called “Siegert Relation” which is used to fit DCS data. In Siegert relation, the relationship between g_2(tau) and g_1(tau) is; g_2(tau) = 1 + beta |g_1 (tau) |^2 . In this equation, beta is an experimental factor which is equal to 1 for an ideal experimental design.Its formal definition is G_2 ({bf{r},tau,t) = <I(bf{r}, t) I(bf{r}, t + tau)> where bf{r} is the source-detector separation/position, tau is the delay time in the autocorrelation, t is time and <...> indicate ensemble averages.

Alternative definition:

Synonym: Normalized Intensity Temporal Autocorrelation (g2)

References:

Related terms: Electric Field Temporal Autocorrelation Function, Diffuse Correlation Spectroscopy  

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