Incomplete active polarimetry: Measurement of the block-diagonal scattering matrix

The problem of measurement of block-diagonal scattering matrix as being part of the so-called incomplete or partial Mueller polarimetry is addressed. It has been shown that non-zero elements of the scattering matrix with block-diagonal structure can be measured using only two elliptical polarizations of input light. Optimal pairs of these polarizations are derived. Utilization of the optimal input polarizations results in halving measurement time and decreasing measurement errors by 30%. ► The problem of measurement of block-diagonal scattering matrix is addressed. ► Block-diagonal scattering matrix can be measured using only two input polarizations. ► Optimal pairs of input polarizations are derived. ► This results in half of measurement time and about 30% decreasing of errors.