Harmonic generation and energy transport in dielectric and semiconductors at visible and UV wavelengths

We study the propagation and momentum transport of the inhomogeneous component of second and third harmonic pulses in dielectrics and semiconductors, at visible and UV wavelengths, focusing on materials like GaP. In these spectral regions GaP is characterized by large absorption, metallic behavior or a combination of both. We show that phase locking causes the generated inhomogeneous signals to propagate through a bulk metallic medium without being absorbed. This means that it occurs even in centrosymmetric materials thanks to the magnetic Lorentz force. We show that the transport of energy and momentum is quite peculiar and it can appear as anomalous, and that the direction of the Poynting vector of some of the harmonic pulses does not follow Snell?s law after crossing the interface. These results make it clear that there are new opportunities in ultrafast nonlinear optics and nanoplasmonics in new wavelength ranges.