In many recent experiments the nonlinear response of the media irradiated with laser light cannot be explained by models in which the Maxwell equations were simplified using slow envelope, paraxial and scalar approximations. It is therefore important to extend the present theoretical models to reduce the gap between theory and experiments. This research will last two years and consist of two parts. In the first part pattern formation beyond the above mentioned approximations will be studied. The second part will be devoted to use pattern formation techniques in high-order harmonic generation for controlling the conversion efficiency enhancing some harmonic and depressing others, having harmonic emission not collinear with the generating fields and with laser intensity much higher than the saturation intensity. The theory of induced representation and the group theoretic interpretation of the Fourier Trasform should be very useful to derive analytical results and new numerical algorithms.