Strain mapping with optically coupled plasmonic particles embedded in a flexible substrate

A change of the optical coupling of plasmonic particles was observed upon deformation of a matrix elastomer where 50 nm gold particles were embedded. The coupling mode showed higher extinction at the polarization perpendicular to the strain direction than the parallel polarization, as deformation induces interparticle distance change. simulation by a multiple multipole program confirmed such a spectral change when the orientation of a coupled particle cluster is deformed. The strain vector map was constructed from the microscopy images with different polarizations at the strain-sensitive wavelength. (C) 2009 Optical Society of America