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Petahertz-bandwidth metrology is demonstrated in the measurement of nonlinear polarization in silica.

A continuum spanning from 300 and 3000 nm is used to synthesize a single-cycle field transient and measure its waveform through electro-optic sampling, speeding up this sensitive technique so that it can access the electric field of visible light.

Individual molecules are now deterministically trapped in few-femtosecond laser pulses. This molecular conveyer belt may become a useful tool for probing ultrafast molecular dynamics.

Combining attosecond metrology and soliton dynamics in hollow-core fibres, the generation of attosecond laser pulses from the deep-ultraviolet to the near-infrared regime and the measurement of attosecond solitons with 350-as durations at optical wavelengths are demonstrated, providing an efficient route to generate intense isolated attosecond pulses complementary to those based on high-harmonic generation in gases.

Combining attosecond science and nanophotonics potentially offers a route to enhance control over light–matter interactions at the nanoscale and provide a promising platform for information processing.

Exposing a fused silica sample to a strong, waveform-controlled, few-cycle optical field increases the dielectric’s optical conductivity by more than 18 orders of magnitude in less than 1 femtosecond, allowing electric currents to be driven, directed and switched by the instantaneous light field.

When a high-intensity laser pulse interacts with a plasma it generates immense fields that can accelerate charged particles. Combining high-speed polarimetry and plasma shadowgraph enables the detailed evolution of this process to be imaged in real time.

High-intensity X-ray sources such as synchrotrons and free-electron lasers need large particle accelerators to drive them. The demonstration of a synchrotron X-ray source that uses a laser-driven particle accelerator could widen the availability of intense X-rays for research in physics, materials science and biology.

Direct measurement of the electric field of light in the near-infrared is experimentally demonstrated, showing that careful optical filtering allows the time-resolved detection of electric field oscillations with half-cycle durations as short as 2.1 fs, even with a 5 fs sampling pulse.

A solid-state device is demonstrated that can detect the absolute offset between the carrier wave and envelope of an ultrashort pulse, the carrier–envelope phase. It holds promise for routine measurement and monitoring of the carrier–envelope phase in attosecond experimental set-ups.

The ultrafast reversibility of changes to the electronic structure and electric polarizability of a dielectric with the electric field of a laser pulse, demonstrated here, offers the potential for petahertz-bandwidth optical signal manipulation.

Laser-generated plasmas are important for the creation of X-ray lasers and attosecond light pulses, but observing the internal dynamics of a plasma is difficult. This paper reports a method for real-time imaging of the electric-field distribution in such plasmas with ultrahigh temporal resolution, yielding a new insight into their behaviour

Continuously adjustable single-cycle waveform spanning from 0.9 to 12.0 μm is obtained by cascaded intrapulse difference-frequency generation in a ZnGeP₂ crystal. The cascade-associated phase response—distinct for different spectral bands—provides a new tuning parameter for waveform adjustment.

Health status transitions are reflected as characteristic changes in molecular composition of biofluids. Here, the authors apply infrared molecular fingerprinting and reveal that blood-based phenotypes are sufficiently stable over time, providing the basis for time- and cost-effective health monitoring.

A vibrational spectroscopy technique that measures the electric field emitted from organic molecules following infrared illumination allows their molecular fingerprints to be separated from the excitation background, even in complex biological samples.

Petahertz-scale optical-field metrology in a pump-probe setting enables the direct observation of how the optical properties of a medium evolve after 1-fs-scale photoinjection.

The structures of crystals, from metals to proteins, have successfully been explored with X-rays. An ultrafast switch turns this idea around and uses a crystal to control the timing of X-ray pulses.

The motion of electrons inside, around and between atoms can be captured with attosecond time resolution. A technique has now been demonstrated that can reveal electron dynamics even without attosecond light flashes.

Studying the dynamics of electrons is important for understanding fundamental processes in materials. Here the ionization of a pair of electrons in argon atoms is explored on attosecond timescales, offering insight into their correlated emission and the double ionization mechanism.

Though strong-field induced carrier excitation allows for exploring ultrafast electronic properties of a material, characterizing post-excitation dynamics is a challenge. Here, the authors report linear petahertz photoconductive sampling in a solid and use it to real-time probe conduction band electron motion.

Characterization of light pulses is important in order to understand their interaction with matter. Here the authors demonstrate a nonlinear photoconductive sampling method to measure electric field wave-forms in the infrared, visible and ultraviolet spectral ranges.

A time-resolved observation of electron tunnelling and the short-lived electronic states that subsequently appear is useful as a new approach to obtain insights in multi-electron dynamics inside atoms and molecules. This technique of 'attosecond tunnelling' is applied to study the cascade of electronic transitions that occur in xenon atoms as a result of their ionization.

A demonstration of attosecond control of the motion and directed emission of electrons from individual silica nanoparticles using few-cycle laser fields opens new possibilities to manipulate electronic processes in nanoscale systems.

Attosecond technology (1 as = 10⁻¹⁸ S) promises the tools needed to directly probe electron motion in real time. These authors report attosecond pump–probe measurements that track the movement of valence electrons in krypton ions. This first proof-of-principle demonstration uses a simple system, but the expectation is that attosecond transient absorption spectroscopy will ultimately also reveal the elementary electron motions that underlie the properties of molecules and solid-state materials.

This article reviews the basic concepts underlying attosecond measurement and control techniques. Emphasis is given to exploring the fundamental speed limit of electronic signal processing that employs ultimate-speed electron metrology provided by attosecond technology.