Optical Chirality of Self-Organized Plasmonic Nanostructures in Thin Photosensitive Films
Arashmid Nahal
Photonic Materials Research Laboratory, Department of Physics, University of Tehran, Tehran, Iran
Abstract- Interaction of He-Ne laser beam with thin AgCl slab waveguide film on a glass substrate, doped by silver nanoparticles, results in formation of self-organized plasmonic nanostructures (SPN), as a grating according to an interference pattern, which is the result of interference of the incident beam with the excited TE-modes of the AgCl film. The grating is made of the silver nanoparticles migrated to the minima of the interference pattern to reduce their total energy. Formation of SPN results in increasing of anisotropy and also induction of optical chirality in the film. As a result, the optical gyrotropy could be induced in the AgCl- Ag film. There are four circumstances with which we can control the amount and sign of rotation of the polarization plane of the probe beam, passing through the samples: (1) changing the polarization state of the incident beam; (2) changing the angle of incidence of the laser beam;
(3) forming two crossed linear SPN and changing the angle between the two nanostructures and (4) using thick AgCl layers to excite, simultaneously, TE0 and TE1 modes of the slab waveguide.
