Determination of Stokes vector from a single image acquisition

Four Stokes parameters (1852) define the polarisation state of light. Measured changes of the Stokes vector of light traversing an inhomogeneous sample are linked to the local anisotropies of absorption and refraction and are harnessed over an increasing range of applications in photonics, material, and space/earth observation. Several independent polarisation sensitive measurements are usually required for determination of the all four Stokes parameters, which makes such characterisation procedure time-consuming or requires complex setups. Here we introduce a single-snapshot approach to Stokes polarimetry in transmission by use of a 4-polarisation camera with the on-chip integrated polarisers. A quarter-waveplate was added in front of the sample and was illuminated by a linearly polarised light. This approach is demonstrated by measuring birefringence $\Delta n\sim 0.012$ of spider silk of only $\sim 6~\mu$m-diameter using microscopy, however, due to its generic nature, it is transferable to other spectral ranges and imaging applications, e.g., imaging from a fast moving satellite or drone or monitoring fast changing events such as phase transitions.Comment: 9 pages, 8 figure

Structural and Thermal Diffusivity Analysis of an Organoferroelastic Crystal Showing Scissor-Like Two-Directional Deformation Induced by Uniaxial Compression

A two-directional ferroelastic deformation in organic crystals is unprecedented owing to its anisotropic crystal packing, in contrast to isotropic symmetrical packing in inorganic compounds and polymers. Thereby, finding and constructing multidirectional ferroelastic deformations in organic compounds is undoubtedly complex and at once calls for deep comprehension. Herein, we demonstrate the first example of a two-directional ferroelastic deformation with a unique scissor-like movement in single crystals of trans-3-hexenedioic acid by the application of uniaxial compression stress. A detailed structural investigation of the mechanical deformation at the macroscopic and microscopic levels by three distinct force measurement techniques (including shear and three-point bending test), single crystal X-ray diffraction techniques, and polarized synchrotron-FTIR microspectroscopy highlighted that mechanical twinning promoted the deformation. The presence of two crystallographically equivalent faces and the herringbone arrangement promoted the two-directional ferroelastic deformation. In addition, anisotropic heat transfer properties in the parent and the deformed domains were investigated by thermal diffusivity measurement on all three axes using microscale temperature-wave analysis (μ-TWA). A correlation between the anisotropic structural arrangement and the difference in thermal diffusivity and mechanical behavior in the two-directional organoferroelastic deformation could be established. The structural and molecular level information from this two-directional ferroelastic deformation would lead to a more profound understanding of the structure–property relationship in multidirectional deformation in organic crystals

Structural and Thermal Diffusivity Analysis of an Organoferroelastic Crystal Showing Scissor-Like Two-Directional Deformation Induced by Uniaxial Compression

A two-directional ferroelastic deformation in organic crystals is unprecedented owing to its anisotropic crystal packing, in contrast to isotropic symmetrical packing in inorganic compounds and polymers. Thereby, finding and constructing multidirectional ferroelastic deformations in organic compounds is undoubtedly complex and at once calls for deep comprehension. Herein, we demonstrate the first example of a two-directional ferroelastic deformation with a unique scissor-like movement in single crystals of trans-3-hexenedioic acid by the application of uniaxial compression stress. A detailed structural investigation of the mechanical deformation at the macroscopic and microscopic levels by three distinct force measurement techniques (including shear and three-point bending test), single crystal X-ray diffraction techniques, and polarized synchrotron-FTIR microspectroscopy highlighted that mechanical twinning promoted the deformation. The presence of two crystallographically equivalent faces and the herringbone arrangement promoted the two-directional ferroelastic deformation. In addition, anisotropic heat transfer properties in the parent and the deformed domains were investigated by thermal diffusivity measurement on all three axes using microscale temperature-wave analysis (μ-TWA). A correlation between the anisotropic structural arrangement and the difference in thermal diffusivity and mechanical behavior in the two-directional organoferroelastic deformation could be established. The structural and molecular level information from this two-directional ferroelastic deformation would lead to a more profound understanding of the structure–property relationship in multidirectional deformation in organic crystals