Upconversion detection of terahertz wave with nanosecond pulse duration using continuous-wave laser

Using an independently operated continuous-wave (CW) laser, we demonstrate effective frequency up-conversion detection of terahertz(THz) wave with nanosecond duration in a DAST crystal. The pump-power dependence of the terahertz up-conversion detection efficiency is investigated both theoretically and experimentally. By comparing two crystals with different heat-dissipation capabilities, the influence mechanism of heat accumulation on the up-conversion efficiency is further revealed. This approach proves the possibility of pulsed terahertz wave detection using a CW pumping without temporal alignment or phase synchronization, providing a simple and flexible scheme for terahertz detection.