A new scheme for efficient generation of coherent and incoherent submillimeter to THz waves in periodically-poled lithium niobate

We show that periodically-poled LiNbO3, when used in the backward configuration can efficiently generate submillimeter to THz waves via such second-order nonlinear processes as optical parametric oscillation, difference-frequency generation, and parametric fluorescence. We estimate the threshold intensity for the parametric oscillation to be below 1 GW/cm(2) and show how the efficiencies of the difference-frequency generation and parametric fluorescence benefit from the large diagonal element of the second-order susceptibility tensor in LiNbO3. (C) 1998 Elsevier Science B.V.