Sub-cycle optical control of current in a semiconductor: from the multiphoton to the tunneling regime

TL;DR

This paper demonstrates ultrafast, all-optical control of electric current in a semiconductor, gallium nitride, within an optical cycle at lower intensities than previously required for insulators, enabling potential PHz electronics.

Contribution

It introduces a method for generating and controlling electric current in a semiconductor using ultrashort optical pulses at lower intensities than in insulators, advancing high-speed electronics.

Findings

Current can be controlled within 2 femtoseconds.

Operation occurs at intensities an order of magnitude lower than in insulators.

Potential for PHz electronic applications.

Abstract

Nonlinear interactions between ultrashort optical waveforms and solids can be used to induce and steer electric current on a femtosecond (fs) timescale, holding promise for electronic signal processing at PHz frequencies [Nature 493, 70 (2013)]. So far, this approach has been limited to insulators, requiring extremely strong peak electric fields and intensities. Here, we show all-optical generation and control of directly measurable electric current in a semiconductor relevant for high-speed and high-power (opto)electronics, gallium nitride (GaN), within an optical cycle and on a timescale shorter than 2 fs, at intensities at least an order of magnitude lower than those required for dielectrics. Our approach opens the door to PHz electronics and metrology, applicable to low-power (non-amplified) laser pulses, and may lead to future applications in semiconductor and photonic integrated circuit technologies.