Controlling and Tracking Electric Currents with Light

This chapter reviews the progress in switching rates of electric current in condensed matter systems. It discusses cases reaching from field‐effect transistors (FETs), which can control currents at frequencies (up to) the order of hundreds of gigahertz, to alloptical injection of currents with ultrashort, coherent pulsed radiation, which offers blistering control of electric currents at the frequency of lightwave oscillations–promising electronics with femtosecond switching times. The chapter discusses the specific proof‐of‐principle experiment, where an electric signal is generated and manipulated in a solid dielectric exposed to the strong electric field of a waveform‐controlled, few‐cycle, visible/near‐infrared (VIS/NIR) laser pulse. The electrical signals depend on the carrier‐envelope phase (CEP) of the ultrashort VIS/NIR pulses. The experiments discussed in the chapter suggests that the electronic properties of a wide‐bandgap material can be altered with a strong optical electric field, reversibly and in a timescale on the order of or smaller than 1fs.