Photoinduced multipolar tensorial patterning in polymer films by coherent control of molecular orientation

Based on an early proposition by R.J. Glauber in 1967, the possibility to break centrosymmetry in molecular media by interference between one- and two-photon absorption pathways has been implemented in polymers throughout the last decade. This effect has been more recently advantageously generalized to optically induce adjustable multipolar molecular ordering in polymer thin films for nonlinear optics. A major benefit of this approach lies in the control of the final molecular orientational distribution by pure Optical parameters such as phase or polarization of write beams. In this article. we extend a tensorial multipolar engineering experiment to encompass tensorial monitoring of photo-induced molecular orientational orders up to the 4th order. Coherent control of optical write beams, combined with real-time tensorial probing of optical properties in the material, provide access to a complete characterization of each excitation pathway contributing to the process. (C) 2002 Academie des sciences/Editions scientifiques et medicales Elsevier SAS.