Effect of flexural stress on fabrication and optical properties of a composite photonic material

We spin coated thin films of poly(methyl) methacrylate (PMMA) polymer doped with 2-[7-(1,3-dihydro-1,3,3-trimethyl-2H-indol-2-ylidene)-1,3,5-heptatrienyl]-1,3,3-trimethyl-3H-indolium iodide (HITC) laser dye onto microscope cover slides under applied flexural stress and found the patterns of scattering (milkiness) to correlate with the spatial variation of the pressure pattern. We further deposited thin gold films on top of the HITC:PMMA films and measured highly unusual transmission spectra of Au collected from strongly deformed (stressed) local areas of the sample. These spectra, which strongly deferred from those of plain Au films deposited onto unstressed glass, could not be described by simple, e.g., Maxwell Garnett, effective media models, calling for a thorough theoretical study.