Terahertz parametric detection with pulse train pump beam

We developed a system that enables detection of THz-wave even when the optical path length of the THz-wave changes, by using a pulse train pump beam in THz parametric detection. First, we investigated the appropriate pulse interval of the pulse train pump beam and the tolerance of the incident timing of the THz-wave. Based on the above, we produced a pulse train pump beam with four pulses at 1.5 ns intervals, and confirmed that continuous THz-wave detection is possible without mechanical operation even when the optical path length of the THz-wave changes about 180 cm.