Multi-frequency Terahertz Generation in Aperiodic Optical Superlattices

We investigate theoretically the generation of multi-frequency terahertz radiation in a LiNbO
₃
superlattice with an aperiodic structure. Such an aperiodic domain-inverted optical superlattice is designed in a quasi-phase-matching scheme. Second-order nonlinear optical rectification of femtosecond pulses gives rise to a terahertz waveform whose multi-frequency modes are determined by the aperiodic structure properties. The relationship between multi-frequency modes terahertz generation and aperiodic structure parameters is also analyzed and studied.