Terahertz Parametric Generator with More Than 10 Wavelengths for One-shot Spectroscopy

We demonstrate simultaneous generation of multi-wavelength terahertz (THz) waves of more than 10 wavelengths toward realizing real-time spectroscopy using THz parametric generation. Simultaneous generation of up to 15 wavelengths was achieved using Stokes beams, generated by cascade processes in a nonlinear optical crystal, as the pump and seed beams for a parametric generator. Using this system, real-time spectroscopy of various reagents was achieved. The fact that as many as 15 wavelengths could be generated simultaneously in the frequency range around 1–2 THz, which is useful for identifying reagents through packaging materials, is important for various spectroscopic applications in the near future.