  We numerically demonstrate inhibition of absorption, optical transparency,
and anomalous momentum states of phase locked harmonic pulses in
semiconductors, at UV and extreme UV frequencies, in spectral regions where the
dielectric constant of typical semiconductors is negative. We show that a
generated harmonic signal can propagate through a bulk metallic medium without
being absorbed as a result of a phase locking mechanism between the pump and
its harmonics. These findings may open new regimes in nonlinear optics and are
particularly relevant to the emerging fields of nonlinear negative index
meta-materials and nano-plasmonics, especially in the ultrafast pulse regime.
