Optical poling of azo-dye-doped thin films using an ultrashort pulse laser

DR1(4-[N-ethyl-N-(2-hydroxyethyl)]amino-4'-nitro-azobenzene)-doped poly(methyl methacrylate) and DR1-doped silica gel thin films were optically polarized by the coherent superposition of the 1500 nm fundamental and the 750 nm second-harmonic light of a 130 fs pulse laser. These films were successfully polarized and saturated in 2 min, despite the transparent seed beams' wavelength for the dye. The mechanism of the optical poling likely occurred in such a way that a multiphoton absorption and a photoisomerization of DR1 induced a polarized structure in the films. (C) 1999 American Institute of Physics. [S0003-6951(99)01428-X].