  A new, different kind of intensity correlation, denoted as polarization based
intensity correlation, is proposed and investigated to study the correlation
between different polarization components of polarization speckle, which has
non-uniform spatial polarization distribution. It is shown both theoretically
and experimentally that the range of the polarization based intensity
correlation for a particular polarization component of the polarization speckle
depends on the spatial average intensity of the speckles corresponding to that
particular polarization component. The experimentally determined nature of the
change of range of the intensity correlation for different polarization
components, due to variation in the average intensity, is found to be matching
well with the theoretical prediction. The existence of non-zero correlation
between two orthogonally polarized speckle patterns, filtered from a partially
depolarized speckle pattern, is also observed. This study may be useful in
exploiting the polarization based intensity correlation for different
applications such as speckle cryptography etc.
