Single-pulse time-resolved terahertz spectroscopy of sub-millisecond time dynamics

TL;DR

This paper introduces a high-speed, real-time terahertz spectroscopy technique capable of capturing sub-millisecond dynamics, enabling detailed observation of fast physical and chemical processes with potential industrial applications.

Contribution

It presents a novel dispersive Fourier transform spectroscopy method that achieves 50,000 frames per second for THz data acquisition, allowing real-time monitoring of non-reproducible phenomena.

Findings

Successfully monitored sub-millisecond dynamics of hot carriers in silicon

Achieved 50,000 frames per second data acquisition

Demonstrated potential for rapid industrial process monitoring

Abstract

Slow motion movies are not only fascinating to watch, they also allow us to see intricate details of the mechanical dynamics of complex phenomena. If the images in each frame are replaced by terahertz (THz) waves, such movies can monitor low-energy resonances and reveal fast structural or chemical transitions. Here, we combine THz spectroscopy as a non-invasive optical probe with a real-time monitoring technique to resolve non-reproducible phenomena at 50k frames per second. The concept, based on dispersive Fourier transform spectroscopy to achieve unprecedented acquisition speed of THz spectroscopy data, is demonstrated by monitoring sub-millisecond dynamics of hot carriers injected in silicon by successive resonant pulses as a saturation density is established. We anticipate that our experimental configuration will play a crucial role in revealing fast irreversible physical and chemical processes at THz frequencies with microsecond resolution to enable new applications in fundamental research as well as in industry, notably as a rapid supply chain monitoring system in high-volume manufacturing.