Kilowatt-peak Terahertz-wave Generation and Sub-femtojoule Terahertz-wave Pulse Detection Based on Nonlinear Optical Wavelength-conversion at Room Temperature

摘要

Intense Terahertz (THz)-wave generation and highly sensitive THz-wave detection were obtained by wavelength conversion with nonlinear optical susceptibility χ~((2)) of LiNbO_3 crystals.Maximum peak output of about 50 kW(5 μJ/pulse) was demonstrated in an injectionseeded THz-wave parametric generator pumped by post-amplified emission from a microchip Nd:YAG laser. Using the sub-nanosecond pulse duration of the laser proposed herein provides effective mitigation of stimulated Brillouin scattering in LiNbO_3, producing higher gain for wavelength conversion between near-infrared (near-IR) pump light and THz waves. Monochromatic THz radiation was obtained in the continuous tuning range of 0.7–2.9 THz. Additionally, highly sensitive THz-wave detection was demonstrated based on up-conversion from THz waves to near-IR light as well as efficient THz-wave generation. The signal generated with non-collinear phase-matching condition showed spectroscopic detection on the screen apart from the LiNbO_3 crystal. Highly sensitive detection with minimum energy of about 80 aJ/pulse (0.8 μW at peak) and a large dynamic range of more than 100 dB were achieved in this experiment.