Analysis of Mueller matrix elements measurement error influence on its physical realisability

One of the main aspects of the Mueller matrix measurement is the physical realisability of the Mueller matrix. The condition for the physical realisability of Mueller matrices is the transformation of the Poincare sphere of the probing radiation to the Poincare sphere of the output radiation. In practice, it means, that the polarization degree of the output radiation must be in a range from 0 to 1 for any polarization state of the probing radiation. But there can be a situation, when the experimentally measured Mueller matrix may give a polarization degree of output radiation more than 1, and so an unrealisable Stokes vector. Such a Mueller matrix is called physically unrealisable. But, in practice, the availability of measurement error may cause a situation, when the experimental (properly measured) Mueller matrix of a real object is physically unrealisable. Thus, conditions of physical realisability, taking into account the Mueller matrix elements measurement error, are obtained