Modulation of coherence-polarization property of speckles using a birefringent scatterer.

ABSTRACT

The change of the spatial coherence-polarization (CP) property of a speckle pattern due to the modulation of birefringence in a scattering medium is investigated experimentally. The birefringence is introduced to the scattering medium by attaching layers of overhead projector (OHP) sheets to it. It is shown that the spatial polarization distribution can be tuned from a uniformly polarized case to a randomly polarized case by increasing the number of OHP sheets. The change of the spatial CP property with the number of OHP sheets is investigated from the study of the spatial degree of coherence and the degree of polarization, and these variations are further confirmed from the probability density function of the intensity of the speckle pattern and from the measurement of the generalized Stokes parameters. The effect of the change of the number of OHP sheets on the visibility of the intensity correlation function and the quality of the object retrieved through the scattering medium are also investigated.