Surface-Emitting THz Generation in Two-Dimensional Quasi-Phase-Matching Structure

Novel schemes to achieve surface-emitting multi-and nearly single-cycle THz generation by optical rectification in two-dimensional quasi-phase-matching (2-D QPM) structures are proposed. Placing 1-D phase mask in front of a conventional 1-D periodically poled lithium niobate (PPLN) crystal forms the periodic pattern that is directed perpendicular to the existing PPLN's grating vector. It is shown that the scheme enables multi-cycle THz pulse generation with 0.37 MW power and 24 μJ energy at a pump pulse energy of 3.4 mJ.