Nonlinear Photonic Engineering: Physics and Applications

Engineering of new nonlinear materials, structures and devices with enhanced figures of merit has acted over the two last decades as a major driving force in optics: electrooptic polymers have emerged in this context as a sound basis for a currently maturing integrated optics technology with a variety of industrial applications at stake. We report here on a major turning point in this field whereby nonlinear optical phenomena, while remaining a major functional end-goal, are being furthermore implemented in the elaboration process itself. Coherent multiphoton processes appear indeed as unique tools to pattern linear and nonlinear structures to a sophistication level out of the reach of earlier technologies. We will review the basic physical phenomena involved which mainly pertain to quantum interferences between multiphoton excitation pathways in photosensitive media. Multipolar nonlinear patterns reflecting the multipolar symmetry of controllable polarization states of the coherent writing beams can be permanently or imprinted on a variety of substrates from films to waveguides, or gratings.