Anisotropy and Second Order Nonlinear Optical Properties Induced by Photoisomerization of Azo Dyes in polymeric films

In order to obtain second order nonlinear optical properties in doped (or functionalized) polymer films, it is necessary to orient the polar dopant molecules (poling process) and to insure a long term stability of this orientation. Other applications of organic films, such as writing polarization gratings by photoinduced anisotropy, deal with alignment of molecules (i.e. an anisotropic but centrosymmetric distribution).