Sub-cycle slicing of phase-locked and intense mid-infrared transients

Abstract

We demonstrate sub-cycle manipulation of mid-infrared optical waveforms in the time domain. This goal is accomplished via efficient reflection at a semiconductor surface induced by femtosecond interband excitation. The ultrafast response of this process allows slicing of high-field multi-terahertz transients down to the single optical cycle. Ultrabroadband and phase-stable transients with peak amplitudes beyond 10 MV cm ^−1 are obtained, paving the way for efficient coherent control of light–matter interaction in the non-perturbative regime. The microscopic analysis of electron–hole plasma generation in germanium reveals a decisive role of two-photon absorption allowing efficient slicing up to mid-infrared frequencies.

Keywords

• ultrafast phenomena
• terahertz spectroscopy
• pulse shaping