  We theoretically predict and experimentally demonstrate inhibition of linear
absorption for phase and group velocity mismatched second and third harmonic
generation in strongly absorbing materials, GaAs in particular, at frequencies
above the absorption edge. A 100-fs pump pulse tuned to 1300nm generates 650nm
and 435nm second and third harmonic pulses that propagate across a 450
micron-thick GaAs substrate without being absorbed. We attribute this to a
phase-locking mechanism that causes the pump to trap the harmonics and to
impress them with its dispersive properties.
