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Measuring acoustic phonons across the Brillouin zone reveals important information on electrical and thermal transport in materials. Temnov et al.generate giant acoustic strain pulses in gold/cobalt bilayers and monitor their nonlinear reshaping in the gold layer with plasmonic interferometry.

The ability to coherently manipulate single electrons and photons is vital for quantum information processing. Experiments now demonstrate optical initialization, manipulation and probing of a single quantum dot on femtosecond timescales, revealing signatures of interaction effects, optical gain and the ability to change the number of quanta in a light pulse by one.

Two-colour modulation spectroscopy of laser field-driven electrons uncovers the suboptical-cycle strong-field emission dynamics from nanostructures with attosecond precision by measuring photoelectron spectra of electrons as function of the relative phase between the two colours.

Based on a passively phase-locked superposition of a dispersive wave and a soliton from two branches of a femtosecond Er-doped fibre laser, researchers demonstrate that single cycles of light can be achieved using existing fibre technology and standard free-space components. The pulses have a pulse duration of 4.3 fs, close to the shortest possible value for a data bit of information transmitted in the near-infrared.

When photons impinge on a material, free electrons can be created by the photoelectric effect. The emitted electron current usually fluctuates with Poisson statistics, but if squeezed quantum light is applied, the electrons bunch up.

Colloidal quantum dots are efficient nanoscopic light emitters with interesting applications from optoelectronics to biomedical imaging. Their polarizability has now been measured directly by probing the electronic response without electrical contacts.

As electronic devices shrink, the interaction between electrons and the silicon crystal lattice, described in terms of 'quasiparticles', is a central issue. Ultrashort laser pulses can track the birth of such a quasiparticle.

Optical antennas are able to concentrate light on a scale much smaller then the wavelength. Bow–tie–shape nanostructures are one example. It is now possible to tune the response of such an antenna by precisely moving one half of the bow tie.

Researchers report the direct observation of ultrafast magnetic dynamics using the magnetic component of highly intense terahertz wave pulses with a time resolution of 8 fs. This concept provides a universal ultrafast method of visualizing magnetic excitations in the electronic ground state.

The nitrogen-vacancy (NV) centre, a naturally occurring impurity in diamond crystals, has a unique, long-lived single-electron spin state that can be controlled and detected optically. This paper demonstrates the first steps towards a sensitive, high-resolution imaging technique in which these diamond spins are exploited. It is shown that the location of single NV spins can be determined with nanometre scale resolution, at ambient conditions, using magneto-optical spin detection.

Active switching of plasmons by an external magnetic field is demonstrated in a metal–ferromagnet–metal structure. The strong modulation, combined with possible all-optical magnetization reversal induced by femtosecond light pulses, opens the door to ultrafast magneto-plasmonic switching.

Carrier-envelope-phase control of the electronic current over a laterally confined tunnelling gap a few nanometres wide yields current densities above 50 MA cm^–2 driven by picojoule-level optical pulses at room temperature.

In strong enough electric fields the non-linear response of electrons in crystals is expected to lead to spatial localization but so far this has only been seen in artificial structures. Schmidt et al. present evidence of this Wannier-Stark localization effect in bulk GaAs driven by intense mid-infrared pulses.

Berghoff et al. discover that polycrystalline MAPbI₃ undergoes transient Wannier Stark localization at moderate field strengths, exhibiting substantial optical modulation with a fast response time. Since the polycrystallinity does not hinder the switching behaviour, this low-cost material is promising for light modulation and photonic applications.

A general theoretical picture regarding the generation and the detection of extremely short pulses of squeezed vacuum light is provided, allowing the treatment of arbitrary wavepackets of quantum light intrinsically in the time domain.

Single-cycle interferometric autocorrelation measurements of electrons tunnelling across the gap of a plasmonic bowtie antenna and quantitative models provide insight into the physical interactions that drive the electron transfer.

The traditional scheme to measure an electric-field waveform beyond radio frequencies requires the challenging synthesis of gate pulses shorter than half of the field’s oscillation period. The authors circumvent this problem by measuring the electric field transient via a third-order nonlinear interaction without resorting to high-energy laser pulses.