Interpreting Intensity Speckle as the Coherency Matrix of Classical Light

Abstract

We show that an intensity speckle can be directly interpreted as the properties of incident light amplitude, phase, polarization, and coherency over spatial positions. Revisiting the speckle-correlation scattering matrix method [Lee and Park, Nat. Comm. 7, 13359 (2016)], we successfully extract the intact information of incident light from an intensity speckle snapshot as the form of a coherency matrix. The idea is experimentally verified by introducing the peculiar states of light that exhibit uneven amplitude, phase, polarization, and coherency features. We also find substantial practical advantage of the proposed method compared to the conventional coherency matrix measuring techniques such as Stokes polarimetry. We believe this physical interpretation of an intensity speckle could open a new avenue to study and utilize the speckle phenomenon in vast sub fields of wave physics.