Space Intensity Correlations in the Near Field of the Scattered Light: A Direct Measurement of the Density Correlation Function $\mathit{g}\left(\mathit{r}\right)$

We show that the two point intensity correlation in the near field of the scattered light is directly related to the two point density correlation $g\left(r\right)$. Preliminary measurements on two sets of calibrated random pinholes of 140 and $300\mu \mathrm{m}$ diameters, and on aqueous solutions of latex spheres of $5$, $10$, and $40\mu \mathrm{m}$ are reported. A discussion on the desirability of the technique as a simple and powerful alternative to low angle scattering will be presented.