Real-time Rapid-scanning Time-domain Terahertz Radiation Registration System with Single-digit Femtosecond Delay-axis Precision

we demonstrate a real-time terahertz time-domain electric field registration system, with the system utilizing a permanent-magnet electrodynamic exciter (mini-shaker) with its movement being resolved via an interferometric tracking method. This system is used to record a terahertz electric field, with the signal being encompassed within a scan range of several picoseconds and the system being capable of realizing a single-digit femtosecond precision in the delay axis. The real-time rapid-scan system is shown to exhibit a 47 dB signal dynamic range for a THz electric field measurement consisting of the average of 300 scans. Measured THz signals show excellent agreement with the traditional step-scan system. As the developed system permits real-time monitoring of terahertz electric fields (along with a higher delay-axis precision) compared to traditional step-scan terahertz time-domain spectroscopy), we envision this system being used for critical applications such as environmental gas detection, security checks, radar monitoring, among others.