Funke Sebastian, Duwe Matthias, Balzer Frank, Thiesen Peter H, Hingerl Kurt, Schiek Manuela
Accurion GmbH, Stresemannstr. 30, D-37079 Göttingen, Germany.
Centre for Photonics Engineering, University of Southern Denmark, Alsion 2, DK-6400 Sønderborg, Denmark.
J Phys Chem Lett. 2021 Apr 1;12(12):3053-3058. doi: 10.1021/acs.jpclett.1c00317. Epub 2021 Mar 19.
Polycrystalline textured thin films with distinct pleochroism and birefringence comprising oriented rotational domains of the orthorhombic polymorph of an anilino squaraine with isobutyl side chains (SQIB) are analyzed by imaging Mueller matrix ellipsometry to obtain the biaxial dielectric tensor. Simultaneous fitting of transmission and oblique incidence reflection Mueller matrix scans combined with the spatial resolution of an optical microscope allows to accurately determine the full biaxial dielectric tensor from a single crystallographic sample orientation. Oscillator dispersion relations model well the dielectric tensor components. Strong intermolecular interactions cause the real permittivity for all three directions to become strongly negative near the excitonic resonances, which is appealing for nanophotonic applications.
通过成像穆勒矩阵椭偏仪分析具有不同多色性和双折射的多晶织构薄膜，该薄膜由具有异丁基侧链的苯胺基方酸（SQIB）的正交晶型多晶型物的定向旋转域组成，以获得双轴介电张量。透射和斜入射反射穆勒矩阵扫描的同时拟合与光学显微镜的空间分辨率相结合，使得能够从单个晶体学样品取向准确确定完整的双轴介电张量。振子色散关系很好地模拟了介电张量分量。强分子间相互作用导致在激子共振附近所有三个方向的实介电常数都变得强烈为负，这对纳米光子学应用很有吸引力。
