Ultrafast plasma-based terahertz modulator

Abstract

Plasma is the optimal choice for acquiring and modulating the extremely high visible and near-infrared light. However, few attempts have been made to apply this strategy for the terahertz (THz) wave modulation in an ex situ manner. Here, we show a laser-driven plasma-based THz modulator (PTM) to ex situ control the incident THz waves. The presented PTM allows for the amplification or extinction of the incident THz waves covering 0.1–2.0 THz within a few picoseconds, simply by adjusting its dipole phase. This modulation is a result of the interaction between the PTM’s dipole and THz wave, which can be accurately reproduced by the spectral analysis method. Our technique offers promising opportunities to explore the plasma-based THz optics and potential applications across different disciplines, such as THz-sensing and near-field THz technology.