Mueller matrix characterization of flexible plastic substrates

- Optical constants of flexible plastic substrates including PMMA, COC, PET, PEN, and PI substrates.
- Classification of birefringent plastic substrates using Mueller matrix spectroscopic ellipsometry data.
- Full 16 Mueller matrix measurement and analysis strategy for optically biaxial plastic substrates.

This work reports on Mueller matrix spectroscopic ellipsometry characterization of various flexible plastic substrates that are optically anisotropic with varying degrees of birefringence. The samples are divided into three groups according to the suggested characterization strategy: low birefringence, high birefringence, and twisted birefringence. The first group includes poly(methyl methacrylate) and cyclic olefin copolymer substrates. These are modeled with biaxial anisotropy for the real part of the refractive index while the imaginary part is approximated as isotropic due to small light absorption. The second group includes polyethylene terephthalate and polyethylene naphthalate substrates, which are modeled with biaxial anisotropy for both real and imaginary refractive indices. Lastly, a polyimide substrate is described as two birefringent layers with twisted in-plane orientation.

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