チ工レンコフ型位相整合方式による差周波光混合テラへルッ波発生

摘要

We demonstrated a Cherenkov-type phase -matching method for monochromatic THz -wave generation using the difference frequency generation process with a lithium niobate crystal,which resulted in high conversion efficiency and wide tunability.We successfully generated monochromatic THz waves across the range 0.2-2.5 THz. We obtained efficient energy conversion in the low frequency region below 0.5 THz,and achieved a flat tuning spectrum by varying the pumping wavelength during THz-wave tuning. Furthermore, we decreased the phase-mismatch that originates in beam diameter by optimizing the pump beam shape with cylindrical lens. The increase of the THz-wave output was confirmed by decreasing the phase mismatching.