Characterization of passivity in Mueller matrices

TL;DR

This paper rigorously characterizes passive Mueller matrices, providing necessary and sufficient conditions for passivity, and offers a framework to identify matrices with maximal transmittance, aiding in polarimetry analysis.

Contribution

It establishes complete criteria for passivity in Mueller matrices and introduces a decomposition method to identify optimal transmittance properties.

Findings

Derived necessary and sufficient conditions for passivity.

Presented a decomposition framework for Mueller matrices.

Provided a criterion to validate experimental Mueller matrices.

Abstract

Except for very particular and artificial experimental configurations, linear transformations of the state of polarization of an electromagnetic wave result in a reduction of the intensity of the exiting wave with respect to the incoming one. This natural passive behavior imposes certain mathematical restrictions on the corresponding Mueller matrices associated to the said transformations. Although the general conditions for passivity in Mueller matrices were presented in a previous paper [J. J. Gil, J. Opt. Soc. Am. A 17, 328-334 (2000)], the demonstration was incomplete. In this paper, the set of two necessary and sufficient conditions for a Mueller matrix to represent a passive medium are determined and demonstrated on the basis of its arbitrary decomposition as a convex combination of nondepolarizing and passive pure Mueller matrices. The procedure followed to solve the problem provides also an appropriate framework to identify the Mueller matrix that, among the family of proportional passive Mueller matrices, exhibits the maximal physically achievable intensity transmittance. Beyond the theoretical interest on the rigorous characterization of passivity, the results obtained, when applied to absolute Mueller polarimetry, also provide a criterion to discard those experimentally measured Mueller matrices that do not satisfy the passivity criterion.