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The propagation of coherent light through a random scattering medium generates speckle pattern. Although the speckle is random in nature, the object information is scrambled into it. The scrambled object information can be retrieved using off-axis holographic technique where the retrieval is made from coherence hologram which is constructed from the interferogram formed by object speckle and a tilted reference speckle. It is shown that the SNR of the object retrieved from the coherence hologram, calculated from the far-field intensity correlation of the interferogram, depends on the average number of reference speckles. The effect of average number of reference speckles on the SNR of the retrieved object in off-axis holographic technique is investigated experimentally by changing the reference speckle while keeping the object speckle unchanged. The experimental observations are presented in this paper.

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In this Letter, we propose and experimentally demonstrate a new, to the best of our knowledge, non-interferometric and highly stable technique to unscramble the incident orbital angular momentum (OAM) state and quantitatively measure the phase structure from the non-imaged random light. A new theoretical basis is developed and also verified by numerical simulation and experimental demonstration. We also quantitatively investigate the OAM modes of the incident light using orthogonal projection.

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.