摘要： Nonlinear metamaterials have revolutionized nonlinear optics, allowing novel abilities that expand the current available nonlinear material capabilities. Due to their unique response, nanoparticles (NP's) have been the subject of research in numerous fields ranging from physics, engineering, biology, medicine and others. Understanding their physical mechanism and properties has enabled unprecedented capabilities in linear and nonlinear optics, sensing, theragnostic biomedical optics, material classifications of molecular structures as complicated as DNA or sensitive as oxygen singlets and much more [1-4]. A complete theoretical description, based on the nonlinear scattering theory, has been found suitable to describe the geometrical contribution of nanostructures (NSs) to their nonlinear response [5]. Yet, until now, a comprehensive theory has been investigated only for the instantaneous nonlinear response. A full response, including the resonant non-instantaneous behavior brought about by their resonant linewidth, has not yet been studied. We experientially demonstrate variance in the nonlinear response by coherently controlling the electric field. We show, for the first time to our knowledge, resonant non-instantaneous properties by coherent control measurements of nonlinear second harmonic generation (SHG) in resonant media. (see Figure 1). In contrary to common perception, we find that transform limited pulses do not yield the strongest nonlinearity in SHG. Approaching strong fields, a decrease in nonlinear behavior is not captures in traditional nonlinear models. We develop a theoretical framework, analogous to a resonant 3 level interaction, capturing non-instantaneous resonant phenomena portraying resonant effects beyond the weak field two-photon description. These include deviations from the conventional SHG nonlinearity which commonly is proportional to the square of the fundamental field intensity (see Figure 2.a). We also show that with changing the localized surface plasmonic resonant wavelength relative to the source's central wavelength, a shift in energy distribution and intensity emerges in the SH process pointing to the relative position of the resonant frequency (see Figure 2.b).