Tuning the optical isotropic point of mixed crystals of ethylenediammonium sulfate/selenate

Abstract

In anisotropic crystals, optical isotropic points are wavelengths where linear birefringence disappears because the refractive indices for both eigenmodes are accidentally equivalent. Here, the optical isotropic point of ethylenediammonium selenate (EDSe) is tuned by generating a solid-solution series of EDSe doped with sulfate. Mueller matrix polarimetry and single-crystal X-ray diffraction are used to correlate changes in linear birefringence with the crystal composition of EDS x Se 1Àx . A scheme for using mixed crystals with isotropic points as tunable birefringent optical bandpass filters is proposed and their performance is modeled. research papers J. Appl. Cryst. (2020). 53, 51-57 Melissa Tan et al. Tuning the optical isotropic point of mixed crystals 57

Anisotropic Circular Dichroism in Aligned Chiral Tellurium Nanorods

“…Kahr and coworkers studied the chiroptical activity of single molecular crystals, where the molecular orientation is well-defined with respect to the incident light. [2][3][4][5] Since such crystals would typically possess also strong linear anisotropies (linear dichroism and/or linear birefringence), Mueller matrix polarimetry is required to separate circular chiroptical effects from linear ones. Thin films of molecular assemblies such as light-harvesting complex II and peptides have been previously fabricated within lipid bilayers and multilayers to study their anisotropic CD.…”