Optical Chirality Determined from Mueller Matrices

Abstract

Optical chirality, in terms of circular birefringence and circular dichroism, is described by its electromagnetic and magnetoelectric material tensors, and the corresponding optical activity contributes to the Mueller matrix. Here, spectroscopic ellipsometry in the spectral range 210–1690 nm is used to address chiral phenomena by measuring Mueller matrices in transmission. Three approaches to determine chirality parameters are discussed. In the first approach, applicable in the absence of linear polarization effects, circular birefringence and circular dichroism are evaluated directly from elements of a Mueller matrix. In the second method, differential decomposition is employed, which allows for the unique separation of chirality parameters from linear anisotropic parameters as well as from depolarization provided that the sample is homogeneous along the optical path. Finally, electromagnetic modeling using the Tellegen constitutive relations is presented. The last method also allows structural effects to be included. The three methods to quantify optical chirality are demonstrated for selected materials, including sugar solutions, α-quartz, liquid crystals, beetle cuticle, and films of cellulose nanocrystals.

Spatially resolved chiroptical study of thin films of benzo[1,2‐b:4,5‐b’]dithiophene‐based oligothiophenes by synchrotron radiation electronic circular dichroism imaging (SR‐ECDi) technique

“…[35][36][37] On the one hand, custom-built Mueller matrix polarimetry microscopes [38] have found successful applications in the study of polycrystalline spherulites of D-sorbitol [34] and of conjugated polymers. [39] On the other, commercial benchtop ellipsometers have been successfully applied for spatially resolved Mueller matrix spectroscopic ellipsometry measurements, [40] with successful applications in the 2D-investigation of thin films of chiral π-conjugated small molecules [41,42] and polymers. [43] Other techniques have been more recently developed, based on two-photon fluorescence scanning confocal microscopy, [44] scanning near-field optical microscopy [45,46] or synchrotron radiation ECD (SR-ECD).…”

Chiral, Magnetic, and Photosensitive Liquid Crystalline Nanocomposites Based on Multifunctional Nanoparticles and Achiral Liquid Crystals

“…LC-B as a neat material (Figure S11, Supporting Information) and LC-B doped with NPs-4 ( NC-8 ) were also analyzed by circular dichroism (CD) spectropolarimetry both in solution for neat NPs-4 (Figure S12, Supporting Information) and in thin films of the doped bulk material (Figure ). Currently, advanced techniques (such as Mueller matrix polarimetry) allowing for variation of the azimuthal orientation of the measured thin film sample are frequently used to determine induced chirality of a material, − preferentially to CD measurements . However, thin film CD of bulk materials has also been successfully used to determine the induction of chirality, particularly in LC phases. − ,− Since the equipment for measuring induced circular dichroism determination has been available to our team, we decided to use this technique to assess chirality induction in the studied sample.…”

Chiral superstructures of inorganic nanorods by macroscopic mechanical grinding

“…7 ), which thereby rules out the effect of linear birefringence (LB). We note that the above technique is a preliminary tool to identify the contribution of LD to the observed CD in a commercial spectropolarimeter, and more advanced techniques, such as Mueller Matrix Polarimetry, could identify the optical chirality with better precision 51 , 52 .

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