When light interacts with low-dimensional systems, new optical new interesting phenomena can arise because of the reduced dimensionality. Classic examples include quantum dots with discrete electronic energy levels or plasmon resonances of metallic nanoparticles. In addition to the dimensionality or shape, the light-matter interaction can be further tuned by using optical nonlinearities. Typically, the induced polarization currents depend linearly on the intensity of the radiation field. However, when the linear relationship breaks down new interesting phenomena arise like frequency conversion or intensity dependent refractive index. We combine this new possibility with the interesting properties of low dimensional systems and use them for applications ranging from subdiffraction resolution imaging to on-chip frequency conversion.