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Optically generated microwaves offer exceptionally low noise, crucial for radar and communications. Here, authors demonstrate a compact photonic chip-based interleaver multiplying pulse rates of mode-locked lasers to 14 GHz, significantly enhancing microwave power and reducing phase noise.

Here, the authors develop an antiferromagnet/topological insulator heterostructure, MnSe/(Bi,Sb)₂Te₃, to obtain laser-induced transient magnetic moment and optically controllable circularly polarized ultrafast terahertz pulse generation, under zero external magnetic field.

Characterisation of optical frequency electric fields and its integration within ultrafast currents in nanostructures is a crucial step for the development of petahertz electronics devices. Here the authors demonstrate singleshot measurement of the phase of a laser pulse with on-chip arrays of hundreds of metallic nanoantennas.

Amplification of laser pulses is key for ultrafast and broadband measurements in physics, biology, and chemistry. Here, the authors show that a femtosecond pulse amplifier, providing 800 Watts of peak power, can be integrated on a photonic chip.

Researchers present a waveform synthesis scheme that coherently multiplexes the outputs from two broadband optical parametric chirped-pulse amplifiers. The technique provides control at the sub-cycle scale and generates high-energy ultrashort waveforms for use in strong-field physics experiments.

A terahertz-driven photogun with field gradients of 3 GV m⁻¹ is demonstrated by using a few microjoules of single-cycle terahertz radiation. The emitted electrons are accelerated up to 14 keV and can be focused down to 90 μm. The electron bunch is further compressed to 167 fs.

Scientists report a record-low integrated timing error of less than 13 as between phase-locked optical pulse trains emitted from two, nearly identical 10 fs Ti:sapphire lasers. The uniform pulse trains will enable many measurements based on the synchronization of pump–probe experiments.

Pulses of light offer a way to create particle accelerators that are a fraction of the size of conventional approaches. Here, the authors demonstrate the linear acceleration of electrons with kiloelectronvolt energy gain and in extremely short bunches using optically-generated terahertz pulses.

Femtosecond-scale synchronization using mode-locked lasers has been limited to periods of just a few minutes. Now it is shown that, by combining a number of laser techniques, sub-10-fs-precision synchronization of remote lasers and microwave sources is possible for more than 10 hours.

Attosecond pulse generation needs improvements both in terms of tunability and photon flux for next level attosecond experiments. Here the authors show how to control the HHG emission and its spectral-temporal characteristics by driving the IAP generation with synthesized sub-cycle optical pulses.

Photoemission is usually driven by the energy of the illuminating laser pulses, but in the strong-field regime, the photoemission from an array of plasmonic nanoparticles is shown to be controlled by the light’s electric field.

Searches for extrasolar planets using the periodic Doppler shift of stellar spectral lines have recently achieved a precision of 60 cm s⁻¹, sufficient to find a 5-Earth-mass planet in a Mercury-like orbit around a Sun-like star. The fabrication of an 'astro-comb' that should allow a precision as high as 1 cm s⁻¹ in astronomical radial velocity measurements is reported

A CMOS-compatible watt-class power amplifier based on large-mode waveguide technology is realized with an on-chip output power reaching ~1 W within a footprint of ~4 mm², enabling integrated photonics to tackle true systems level integration.

On-chip optical-field emission devices may be useful for fast electronics and signal processing. Here the authors show a compact on-chip light phase detector capable of monitoring photocurrents oscillating at optical frequencies using electrically connected arrays of plasmonic bow-tie nanoantennae.

Coherent Rabi flopping and coherent pulse reshaping are directly observed in an operating quantum cascade laser. The findings indicate the potential for coherent effects to be exploited in mode locking, and may stimulate new approaches for generating short pulses in quantum cascade lasers.

The mechanisms of high-order harmonic generation in bulk system and dilute gas are different. Here the authors use first-principle methods to explore the ellipticity dependence and control of the HHG in periodic solids by involving the interband and intraband dynamics in Si and MgO.

Air-based acousto-optic modulation is shown to be able to efficiently control gigawatt-scale, ultrashort laser pulses.

The intermolecular dynamics of liquid water impact most biological processes. Here, the authors use intense terahertz electromagnetic pulses to generate a transient, out-of-equilibrium state of the water network to show that the molecules become oriented and probe the polarizability of this anisotropic state.

An integrated high-energy laser that combines a passively Q-switched laser cavity based on a silicon-nitride photonic integrated circuit with an optically pumped gain layer consisting of thulium-doped alumina is reported, representing a pivotal advancement in integrated pulsed lasers.

By sending few-microjoule single-cycle terahertz pulses to a segmented terahertz electron accelerator and manipulator, 70 MV m^–1 peak acceleration fields, 2 kT m^–1 focusing gradients, 140 µrad fs^–1 streaking gradient and bunch compression to 100 fs are achieved.

Optical waveforms with a 1.7 octave spectrum and 0.6 optical cycle duration are generated at a central wavelength of 1.4 μm by parametric waveform synthesis. The output pulse energies amount to >500 μJ with fluctuations of 1% r.m.s. over 1,000 shots.

Stable sub-cycle pulses in the mid-infrared region allow damage-free investigation of electron dynamics in solids. Here, the authors develop a suitable source to this end which is based on an optical parametric amplifier.

An on-chip, sub-optical-cycle sampling technique for measuring arbitrary electric fields of few-femtojoule near-infrared optical pulses in ambient conditions is demonstrated, offering an improvement of roughly six orders of magnitude in energy sensitivity compared with those previous works in the near-infrared.

Optical generation of terahertz radiation is needed for many applications, but gaining high efficiency is still a challenge. The authors report a method to overcome dispersion effects in interfering chirp pulses used for THz pulse production by tuning their relative spectral phase, enabling 0.6 mJ of THz energy output.

The conversion of shaped near-infrared pulses to shaped, energetic, multi-octave-spanning mid-infrared pulses lasting as little as 1.2 optical cycles is made possible by adiabatic difference frequency generation.

Quantum jitter fundamentally limits the performance of microresonator frequency combs. The timing jitter of the solitons that generate the comb spectra is analysed, reaching the quantum limit and establishing fundamental limits for soliton microcombs.

Cheng, Chung et al. develop a compact multimodal, multiphoton microscope for the detection of protein crystals with high sensitivity. This new tool facilitates the identification and detection of protein micro- and nano-crystal suspensions for serial diffraction data collection at X-ray free-electron lasers or high-intensity microfocus synchrotron radiation sources.