  Because of the importance of second harmonic generation in some nonlinear
media, in this paper, we investigated induced second harmonic generation in
diamond where there is no intrinsic second order susceptibility, X(2). The
electric field is proposed to introduce moving susceptibility of the second
order and induce second harmonic generation. Then, spatiotemporal (QPM) is
applied to optimize the induced second harmonic generation. Numerical results
reveals that in this way, the induced second harmonic is found at the frequency
of omega (2) = 2 omega(0) + or - Delta omega rather than omega (0).
