  A new technique based on superposition of two speckle patterns is proposed
and demonstrated for controlled modulation of the spatial polarization
distribution of the resultant speckle. It is demonstrated both theoretically
and experimentally that controlled modulation of the spatial polarization
distribution of laser speckle can be achieved by proper choice of the
polarization states as well as the average spatial intensity of the constituent
speckles. It is also shown that the proposed technique is useful to generate
different speckle patterns with sinusoidal variation in their degree of
polarization, which can be tuned from zero to unity. This technique can find
applications in sensing, biomedical studies, and in determining the rotation of
the electric field vector after passing through a scattering medium.
