Controlling dielectrics with the electric field of light

Abstract

The control of the electric and optical properties of semiconductors with microwave fields forms the basis of modern electronics, information processing and optical communications. The extension of such control to optical frequencies calls for wideband materials such as dielectrics, which require strong electric fields to alter their physical properties. Few-cycle laser pulses permit damage-free exposure of dielectrics to electric fields of several volts per ångström and significant modifications in their electronic system. Fields of such strength and temporal confinement can turn a dielectric from an insulating state to a conducting state within the optical period. However, to extend electric signal control and processing to light frequencies depends on the feasibility of reversing these effects approximately as fast as they can be induced. Here we study the underlying electron processes with sub-femtosecond solid-state spectroscopy, which reveals the feasibility of manipulating the electronic structure and electric polarizability of a dielectric reversibly with the electric field of light. We irradiate a dielectric (fused silica) with a waveform-controlled near-infrared few-cycle light field of several volts per angström and probe changes in extreme-ultraviolet absorptivity and near-infrared reflectivity on a timescale of approximately a hundred attoseconds to a few femtoseconds. The field-induced changes follow, in a highly nonlinear fashion, the turn-on and turn-off behaviour of the driving field, in agreement with the predictions of a quantum mechanical model. The ultrafast reversibility of the effects implies that the physical properties of a dielectric can be controlled with the electric field of light, offering the potential for petahertz-bandwidth signal manipulation.

Quantum-electrodynamical density-functional theory: Bridging quantum optics and electronic-structure theory

“…Thus, we find a Maxwell field defined by Eq. (86). At this level of approximation, our starting point coincides with that adopted in [40].…”

“…When restricting the photons to a cavity, the Kohn-Sham current is then responsible to couple the different photon modes. The coupling terms in the Kohn-Sham current are specifically relevant in the context of, e.g., nanoplasmonics, where the electromagnetic fields are enhanced due to the presence of the plasmons, or in the optical control of currents in solids [86].…”

Ultrafast Control of Strong-Field Electron Dynamics in Solids

“…Bragg-like scattering of electrons was found to contribute to the generation of nonperturbative high-order harmonics in solid samples [7,8]. The reversible field-induced change of absorption in the extreme ultraviolet spectral range was observed by probing the effect of an intense near-infrared field on a thin silica plate using an attosecond pulse of extreme ultra-violet radiation as a probe [9]. A subcycle turn-on of electric current in a dielectric and its manipulation with CEP-stabilized pulses was demonstrated by measuring the residual polarization induced by the laser light [10].…”

“…However, new experiments put these phenomena in a new context, which often leads to nontrivial observations, such as the generation of nonperturbative high-order harmonics in a solid due to Bragg-like scattering at the edges of the Brillouin zone [7,8], a nearly instantaneous change in extreme-ultraviolet absorptivity and nearinfrared reflectivity of a dielectric in the presence of a laser field as strong as several volts perångström [9], or the induction of electric current in an unbiased dielectric by similarly intense laser pulses [10]. Several decades of research on strong-field phenomena in solids and mesoscopic structures provide a solid ground for developing new theoretical models adapted for new experimental conditions.…”

Attosecond transient reflectivity of electron dynamics in germanium

“…Attosecond science holds the promise to unravel the fastest electronic processes in solid-state materials [4,5]. Attosecond transient absorption of nanometer-thick films in particular combines the highest temporal resolution with a good energy resolution.…”