  We present a numerical parametric study of single-cycle electromagnetic pulse
generation in a DAST/SiO2 multilayer structure via collinear optical
rectification of 800 nm femtosecond laser pulses. It is shown that
modifications of the thicknesses of the DAST and SiO2 layers allow tuning of
the average frequency of the generated THz pulses in the frequency range from 3
to 6 THz. The laser-to-THz energy conversion efficiency in the proposed
structures is compared with that in a bulk DAST crystal and a
quasi-phase-matching periodically poled DAST crystal and shows significant
enhancement.
