Interferometric Time Synchronization of a Terahertz Time-Domain Spectroscopy System Driven by a Mode-Locked Laser Diode

Terahertz time-domain spectroscopy (THz-TDS) systems using a monolithic mode-locked laser diode (MLLD) as the light source have the potential to be extremely compact and fast. However, phase sensitive applications require the delay axes of related measurements to be accurately synchronized. In this work, we demonstrate an interferometric synchronization scheme with negligible hardware effort and yet high accuracy by exploiting the high repetition rate of the MLLD.