Active gas-sensing with high-sweeping-speed optically synchronized dual-channel THz signals and a superconducting tunneling mixer

We developed an active gas-sensing system with a superconductor-insulator-superconductor (SIS) mixer and a generator for high-sweeping-speed optically synchronized dual-channel terahertz (THz) signals (GHOST). The developed active gas-sensing system covers a frequency range from 200 to 500 GHz at once and can sweep that frequency range at a speed of 375 GHz/s. With this system, active gas-sensing was carried out with N 2 O gas.