Terahertz parametric generation photonic band gap structure with negligible structural dispersion in the optical...

We present a photonic band gap (PBG) structure (or nonlinear photonic crystal) design for terahertz (THz) wave parametric generation, whose component materials have a small refractive index difference in the near infrared and a large index difference for THz waves. The structural dispersion of such a PBG structure is strong in the THz range but negligible in the optical range. The former allows the phase-matched pump wavelength to be placed in the near infrared to eliminate two-photon absorption of the pump and signal beams. The latter leads to a crystal layer fabrication tolerances of a few micrometers and traditional polishing methods are suitable for device fabrication. The added design flexibility also allows the use of the most efficient crystal orientations.