TY - JOUR
AU - Morikawa, Junko
AB - Polarisation analysis of light–matter interactions established for propagating optical far-fields is now extended into an evanescent field as demonstrated in this study using an attenuated total reflection (ATR) setup and a synchrotron source at THz frequencies. Scalar intensity E2, rather than a vector E-field, is used for absorbance analysis of the s- and p-components of the linearly polarised incident light. Absorption and phase changes induced by the sample and detected at the transmission port of the ATR accessory revealed previously non-accessible anisotropy in the absorption–dispersion properties of the sample probed by the evanescent optical near-field. Mapping of the sample's anisotropy perpendicular to its surface by the non-propagating light field is validated and the cos2 θ absorbance dependence was observed for the angle θ, where θ = 0° is aligned with the sample's surface. A four-polarisation method is presented for the absorbance mapping and a complimentary retardance spectrum is retrieved from the same measurement of the angular dependence of transmittance in structurally complex poly-hydroxybutyrate (PHB) and poly-L-lactic acid (PLLA) samples with amorphous and banded-spherulite (radially isotropic) crystalline regions. A possibility of all 3D mapping of anisotropy (polarisation tomography) is outlined.
TI - Polariscopy with optical near-fields
JF - Nanoscale Horizons
DO - 10.1039/d2nh00187j
DA - 2022-08-22
UR - https://www.deepdyve.com/lp/royal-society-of-chemistry/polariscopy-with-optical-near-fields-ctzRDePdms
SP - 1047
EP - 1053
VL - 7
IS - 9
DP - DeepDyve
ER -