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Summary form only given. It is well known that in dense media the effective field acting on an atom/molecule is no longer the macroscopic field but the so-called local field, which is due to all external sources and to all dipole moments of the atoms/molecules within the sample except the one under consideration. The inclusion of the local field effects gives rise to the prediction of a large number of interesting phenomena in optical systems, such as spectral red shifts, mirrorless optical bistability, "piezophotonic" effects, and enhancement of inversionless gain and absorptionless index in lasing without inversion. As an example, a density of 10/sup 17/ atoms/cm/sup 3/ of sodium atoms is sufficient to give rise to a shift of about 1 GHz of the sodium D line. We analyze here the role of the local field effects on the spatiotemporal dynamics of broad-area homogeneously broadened three-level lasers. In these three-level systems, laser emission in one atomic transition is investigated while an external plane-wave driving laser couples an adjacent transition. Due to the interplay between atomic nonlinearities and light diffraction, the optical wavevector of the generated laser field develops a small component in the transverse plane, i.e., the emitted laser beam is slightly tilted with respect to the cavity-axis.