Polarization gating based on Mueller matrices

Abstract

Abstract. We present mathematical formulae generalizing polarization gating techniques. Polarization gating refers to a collection of imaging methods based on the combination of different controlled polarization channels. In particular, we show how using the measured Mueller matrix of a sample, a widespread number of polarization gating configurations can be evaluated just from analytical expressions based on the Mueller matrix coefficients. We also show the interest of controlling the helicity of the states of polarization used for polarization gating based metrology, as this parameter has an impact in the image contrast of samples. In addition, we highlight as well the interest of combining polarization gating techniques with tools of data analysis related to the Mueller matrix formalism, such as the well-known Mueller matrix decompositions. The method discussed in this work is illustrated with the results of polarimetric measurements done on artificial phantoms and real ex-vivo tissues.

Polarimetric imaging of biological tissues based on the indices of polarimetric purity

“…Therefore, we can assume that the diattenuation effects of the sample are negligible, and the diattenuation information is not useful to improve the image contrast in this case. This result is in agreement with other studies in the literature , where most polarimetric analyses dealing with biological tissues focusses on retardance and depolarization.…”

“…Different polarimetric studies of biological samples have shown that retardance and depolarization are the main polarimetric channels providing significant information of tissues . In addition, the information of samples encoded in the polarization of light strongly depends on the particular structure to be analyzed.…”

“…In the last decades, imaging polarimetry has shown its potential in biomedical applications . This approach has led to enhanced image contrast of samples , and it has provided constitutive information of biological structures . As an example, polarimetric imaging allows determining the organization and density of fibers in tissues , describing the scattering mechanisms in biological samples , determining the degree of birefringence of different structures and so on.…”

“…A proper mathematical synthetization of the MM, or the use of merit functions based on the MMs coefficients, is nowadays used to enhance the image contrast of biological samples. Recently, we have provided the link between PG and MM approaches, proving that some PG configurations can be understood as combinations of MM coefficients .…”

Indices of polarimetric purity to enhance the image quality in biophotonics applications

“…On the other hand, MM measurements, combined with certain associated analytical tools (mainly, MM decompositions), not only allow an enhancement of the image contrast of biological samples, but also permit a physical characterization of the studied samples and the observation of new structures. Although we can define two groups, PGs have been recently linked with MM methods, showing that PG can be generalized as particular cases of a discrete combination of MM coefficients [13].…”