The emergence of coherence among electronic quasiparticles underlies collective quantum phenomena from superconductivity to superradiance. In semiconductors, exciton coherence is generally thought to decay rapidly due to scattering and dephasing, limiting its persistence on ultrafast timescales. Here we demonstrate a light-field-driven mechanism that creates and stabilizes exciton coherence in the layered antiferromagnet CrSBr. We directly record the coherent optical field emitted by excitons and track in real time how a deterministic phase, imprinted by the excitation laser, drives incoherent excitons to synchronize into a collective state. This ensemble remains phase coherent for more than 2 ps, whereas its resonance energy undergoes an ultrafast modulation mediated by spin and lattice interactions. The time-resolved field evolution indicates that the multiple peaks seen in conventional spectra originate from a single excitonic resonance subject to dynamic energy modulation. Our findings establish optical phase imprinting as a mechanism to control and sustain collective order in semiconducting magnets, bridging light-driven dynamics with excitonic and magnetic correlations in layered quantum materials.

We report on a passively carrier-envelope phase (CEP) stable optical parametric amplifier generating two-cycle pulses at 2.1μm with energies of up to 2.2 μJ operating at a repetition rate of 400 kHz, specifically designed for applications in field-resolved spectroscopy. The measured pulse duration is 13.6 fs, resulting in 2 cycles of the carrier wave. Due to the robust CEP-stable front-end design, we achieve exceptional open-loop CEP stability of 250 mrad (rms) and the capability for fast CEP modulation.

Direct time-domain measurements of electric fields enable sub-cycle spectroscopy of light-matter interactions, but established techniques such as electro-optic sampling are constrained in their bandwidth by gate-pulse duration and phase-matching limitations. Alternative approaches have emerged in recent years based on asymmetric interferometric nonlinear cross-correlations with highly nonlinear media, and have demonstrated, for example, the field-resolved study of exciton ensembles. However, these nonlinear cross-correlation-based techniques have been benchmarked almost exclusively by self-referenced pulse characterization rather than by their quantitative spectroscopic performance, and all-optical approaches have received less attention than those based on direct charge emission. Here we extend all-optical asymmetric interferometric cross-correlation to higher nonlinearities in sub-wavelength films and demonstrate field-resolved spectroscopy of the free-induction decay of two ro-vibrational bands of ambient water vapor with a performance comparable to state of the art electro-optic sampling. The measurement spans 190 THz of bandwidth (80 THz to 270 THz) with sub-500 GHz spectral resolution, a spectral intensity dynamic range of six orders of magnitude, and a field-strength noise floor of 100 kV per meter. We anticipate the rapid adoption of here presented all-optical sampling to many experimental settings and a broad impact beyond the ultrafast optics research community as it is drastically simplified in comparison to ionization based techniques and allows the translation of electro-optic-sampling-level sensitivity into higher frequency ranges not previously accessible by conventional tools.

Lightwave electronics offer transformative field-level precision and control at high optical frequencies. While recent advances show that lightwave-driven electron emission from nanoantennas enables time-domain, field-resolved analysis of optical waveforms through a small-signal analysis, the effect of the gate waveform on the measurement transfer function remains unexplored. By generating electrons with a 10-cycle pulse in the optical tunneling regime and perturbing the response with a 1.5-cycle pulse, we experimentally measure the bandwidth limitations imposed by the electron emission process. By comparing these measurements with TDSE simulations and analytical models, we reveal the temporal properties of the electronic response and its impact on the small-signal transfer function. Our results test and confirm the accuracy of the Fowler-Nordheim model in estimating the lightwave electronic response from noble metals. We envision extending these techniques to multi-octave-spanning signals for precise characterization of sub-cycle electronic responses through harmonic frequency mixing.

Field-resolved spectroscopy has been highly influential in the study of light-matter interactions at terahertz and infrared frequencies, such as the investigation of matter under extreme conditions [1], or accessing fundamentals of quantum mechanics by directly measuring vacuum fluctuations in time [2]. However, conventional electro-optic sampling is limited in its accessible bandwidth by the optical gating pulse duration and phase matching constraints. To overcome these limitations, field-resolved measurements based on small-signal perturbation of nonlinear electron emission have been developed [3]–[6]. Due to the extreme nonlinearity of the electron emission, these methods allow to generate sub-cycle attosecond probes with petahertz bandwidth to measure electric field in amplitude and phase with unprecedented bandwidth. The realization of a universal field-resolved spectroscopy platform based on this method has unique challenges, as it requires high repetition rates for sufficient SNR, few-cycle pulses for the generation of almost isolated attosecond electron bursts, long wavelengths in the NIR to MIR for increased ponderomotive energy, microjoule level energies, and carrier-envelope phase (CEP) stability.

Stimulated Raman scattering (SRS) is advantageous for in vivo diagnostic imaging due to its non-destructive, label-free, and chemically selective nature. It can significantly enhance the signal-to-noise ratio compared to the conventional spontaneous Raman scattering process, enabling fast acquisition of Raman signals for hyperspectral imaging. While it is used in various medical fields, such as cancer diagnostics, stain-free histopathology, and pharmaceutical research, its application outside clinical settings or laboratories is limited due to the complexity of the required light source. This study focuses on the development of a portable SRS system based on a tunable dual-output fiber-based light source which can be used not only for medical imaging but also for proximal standoff detection of chemicals and explosives. In order to determine the fiber laser design requirements, we set up a benchtop SRS system using a commercial free-space tunable dual-wavelength laser and experimentally analyze the laser-related factors influencing SRS signal generation, such as wavelength tunability, output power, power ratio of the two incident beams, spectral bandwidth, and pulse duration. Additionally, we evaluate the factors affecting the sensitivity and reproducibility of SRS detection, including the ratio of pump-Stokes beams and the distance between the sample and the detector. Based on the parametric study of SRS detection with the benchtop SRS system, we have determined the design parameters of the new fiber-based SRS source where the broadband pump beam is produced through supercontinuum generation for fast hyperspectral SRS imaging.

We demonstrate a molybdenum silicide superconducting nanowire single-photon detector heterogeneously integrated onto a thin-film lithium niobate waveguide. The detector achieves approximately 50% on-chip detection efficiency at 1550 nm with a jitter of 82 ps when measured at 0.78 K. This demonstration showcases the integration of an amorphous superconductor utilizing conventional fabrication processes without strict cooling and substrate requirements. This paves the way for the integration of additional superconducting electronic components, potentially realizing the full promise of integrated quantum photonic circuits.

Electronic frequency mixers are fundamental building blocks of electronic systems. Harmonic frequency mixing in particular enables broadband electromagnetic signal analysis across octaves of spectrum using a single local oscillator. However, conventional harmonic frequency mixers do not operate beyond hundreds of gigahertz to a few terahertz. If extended to the petahertz scale in a compact and scalable form, harmonic mixers would enable field-resolved optical signal analysis spanning octaves of spectra in a monolithic device without the need for frequency conversion using nonlinear crystals. Here, we demonstrate lightwave-electronic harmonic frequency mixing beyond 0.350 PHz using plasmonic nanoantennas. We demonstrate that the mixing process enables complete, field-resolved detection of spectral content far outside that of the local oscillator, greatly extending the range of detectable frequencies compared to conventional heterodyning techniques. Our work has important implications for applications where optical signals of interest exhibit coherent femtosecond-scale dynamics spanning multiple harmonics.

Attosecond science has demonstrated that electrons can be controlled on the sub-cycle time scale of an optical waveform, paving the way towards optical frequency electronics. However, these experiments historically relied on high-energy laser pulses and detection not suitable for microelectronic integration. For practical optical frequency electronics, a system suitable for integration and capable of generating detectable signals with low pulse energies is needed. While current from plasmonic nanoantenna emitters can be driven at optical frequencies, low charge yields have been a significant limitation. In this work we demonstrate that large-scale electrically connected plasmonic nanoantenna networks, when driven in concert, enable charge yields sufficient for single-shot carrier-envelope phase detection at repetition rates exceeding tens of kilohertz. We not only show that limitations in single-shot CEP detection techniques can be overcome, but also demonstrate a flexible approach to optical frequency electronics in general, enabling future applications such as high sensitivity petahertz-bandwidth electric field sampling or logic-circuits. 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.

Modern day field emitters can fail due to several mechanisms that are not well understood. This paper presents experiments that aim to identify the mechanisms behind failure. Two types of devices, Silicon gated field emitter arrays (Si-GFEAs) and Titanium Silicon Oxy Nitride (TiSiON) lateral field emitter devices were characterized experimentally. Si-GFEAs were tested for arc occurrence time for a fixed gate voltage of 50 V and a fixed collector voltage of 200 V. The emitter was grounded. Initial results from the temporal response experiment show that the emitter experiences arcing first. However, future experiments will provide an accurate identification of the arc initiating electrode. For the planar device, a diode was chosen and IV characterization was performed at 50 degrees C and 400 degrees C. Experiments showed that for an applied collector voltage of 10 V, the field emission current was approximate to 5.5 nA before the heat treatment and was approximate to 2.75 nA after the 400 degrees C heat treatment. This reduction in current could be attributed to the removal of water vapor by heat treatment resulting in the reduction in the surface leakage current.

Lateral field emission devices have been characterized before and after ultraviolet (UV) light exposure. Two types of planar device structures, diode and bowtie, were studied. These nanoscale devices have 9–15 nm tip-to-tip (bowtie) or tip-to-collector (diode) dimensions with the tips fabricated from Au/Ti. Typical currents of 2–5 nA per tip at 6 V were measured. It was observed that after UV exposure, the collected current was reduced by >28% for the case of a bowtie device; whereas the current was reduced by >39% for the case of a diode device. This reduction can be attributed to water vapor desorption on the dielectric surface between the structures, which in turn reduces surface leakage. The Fowler–Nordheim plot showed a straighter line after UV exposure. After the I-V test, the UV-exposed devices were placed on lifetime tests in a vacuum of <10−8 Torr and were biased at 5 V DC. After 2600 h, an abrupt current decrease was observed: ∼25% for the case of the bowtie and ∼28% for the case of the diode device. Scanning electron microscope images of the bowtie and diode devices showed damage to the tips.

Attosecond science has demonstrated that electrons can be controlled on the sub-cycle time scale of an optical wave, paving the way toward optical frequency electronics. Using controlled few-cycle optical waveforms, the study of sub-cycle electron emission has enabled the generation of attosecond ultraviolet pulses and the control of attosecond currents inside of solids. However, these experiments rely on high-energy laser systems not suitable for integration with microcircuits. To move towards integrated optical frequency electronics, a system suitable for integration into microcircuits capable of generating detectable signals with low pulse energies is needed. While current from plasmonic nanoantenna emitters can be driven at optical frequencies, low charge yields have been a significant limitation. In this work we demonstrate that large-scale electrically-connected plasmonic nanoantenna networks, when driven in concert, enable a much higher charge yield sufficient for shot-to-shot carrier-envelope phase detection, which is a hallmark of the underlying sub-cycle processes. We use a tailored sub-2-cycle mid-infrared waveform of only tens of nanojoules of energy to drive in excess of 2000 carrier-envelope-phase-sensitive electrons from interconnected plasmonic nanoantenna arrays that we detect on a single-shot basis using conventional electronics. Our work shows that electronically integrated plasmonic nanoantennas are a viable approach to integrated optical frequency electronics. By engineering the nanoantennas to the particular use case, such as carrier-envelope phase detection, and optimizing the density and total amount, the output signals are fully controlled. This approach to optical frequency electronics will further enable many interesting applications, such as petahertz-bandwidth electric field sampling or the realization of logic gates operating at optical frequencies.

John Fleming demonstrated in 1905 the first vacuum diode based on thermionic electron emission for the rectification of AC electric fields and started an avalanche of developments in microwave electronics such as sensitive wireless receivers or signal amplifiers [1]. Around 100 years later, lasers connected the optical domain with the microwave domain by coherently locking optical frequencies to microwave frequencies with carrier-envelope (CE) offset stable frequency combs, enabling many applications such as precision metrology [2]. To directly drive electronic systems with optical frequencies, many approaches based on carrier-envelope phase (CEP) stable few-cycle NIR pulses, directly driving sub-cycle electron currents at optical frequencies in dielectrics, metal-vacuum-metal junctions, or gases have been investigated [3]–[6]. We present an approach based on the large-scale integration of metallic nanoantennas into conventional electronic readout circuitry; see Figs. 1 a and b. When irradiating an array of $\sim 1000$ antennae with 18 fs, CE-stable pulses having a center wavelength of 2640 nm, repetition rate of 50 kHz, and peak field strengths up to 1.7 Vnm −1 , we observe shot-to-shot changes in CE phase dependent charge amplitudes up to $\sim 3000 \ \mathrm{e}$ , see Fig. 1 c. We further investigated the CE sensitive charge amplitude as a function of field strength and found excellent agreement with models based on the quasi-static tunneling approximation extracting an effective field enhancement of 8 by the antenna structure, in very good agreement with our electromagnetic simulation; see Fig. 1 d.

We report single-shot detection of the carrier-envelope phase of few-cycle mid-infrared waveforms using petahertz electronic networks. Leveraging large-area networks, we demonstrate a charge amplitude of 2,500 electrons per shot, enabling the detection at the full laser repetition rate of 50 kHz.

Inorganic–organic hybrid materials represent a large share of newly reported structures, owing to their simple synthetic routes and customizable properties 1 . This proliferation has led to a characterization bottleneck: many hybrid materials are obligate microcrystals with low symmetry and severe radiation sensitivity, interfering with the standard techniques of single-crystal X-ray diffraction 2,3 and electron microdiffraction 4–11 . Here we demonstrate small-molecule serial femtosecond X-ray crystallography (smSFX) for the determination of material crystal structures from microcrystals. We subjected microcrystalline suspensions to X-ray free-electron laser radiation 12,13 and obtained thousands of randomly oriented diffraction patterns. We determined unit cells by aggregating spot-finding results into high-resolution powder diffractograms. After indexing the sparse serial patterns by a graph theory approach 14 , the resulting datasets can be solved and refined using standard tools for single-crystal diffraction data 15–17 . We describe the ab initio structure solutions of mithrene (AgSePh) 18–20 , thiorene (AgSPh) and tethrene (AgTePh), of which the latter two were previously unknown structures. In thiorene, we identify a geometric change in the silver–silver bonding network that is linked to its divergent optoelectronic properties 20 . We demonstrate that smSFX can be applied as a general technique for structure determination of beam-sensitive microcrystalline materials at near-ambient temperature and pressure.

Chalcogenides in perovskite and the related layered Ruddlesden-Popper crystal structures (chalcogenide perovskites for brevity) are an exciting family of semiconductors but remain experimentally little studied. Chalcogenide perovskites share crystal structures and some physical properties with ionic compounds such as oxide and halide perovskites, but the metal-chalcogen bonds responsible for semiconducting behavior are substantially more covalent than in these more-studied perovskites. Here, we use complementary experimental and theoretical methods to study how the mixed ionic-covalent Zr-S bonds support the electronic structure and physical properties of perovskite BaZrS3 and Ruddlesden-Popper Ba3Zr2S7. We apply theoretical methods to assign features of experimentally measured x-ray absorption spectroscopy (XAS) to particular orbital transitions, enabling a clear physical interpretation of angle-dependent, polarized XAS data measured on single-crystal samples, and an atomistic view of the covalent bonding network that facilitates charge transport. Polarized Raman measurements identify signatures of crystalline anisotropy in Ba3Zr2S7 and enable the first assignments of mode symmetry in this material. Infrared reflectivity reveals electronic transport properties that augur well for the use of chalcogenide perovskites in optoelectronic and energy-conversion technologies.

Organic electronic devices rely on the performance of polymers that are used as active layers. Poly(3,4-ethylenedioxythiophene) (PEDOT) is one of the most studied polymers for organic electronic devices and especially bioelectronics. Because charge carriers move along the polymer backbone (anisotropic charge transport), one of the key challenges is controlling orientation of the polymer in thin films, hence increasing the transport performance. Here, we introduce a method for the oriented growth of PEDOT chains on nanometer-thick self-assembled monolayer (SAM)-modified gold electrodes. We show that, when the gold layer is covered with a SAM that is active for polymer chain growth, a more crystalline film is obtained compared to the surface having a nonactive SAM. We used a nitric acid oxidant to perform the polymerization, which overcomes temperature incompatibility between the gold-supported thiolate monolayers and the polymerization. We characterize the chemical nature and physical properties of the oriented PEDOT film. Reaction conditions and ease of processing appeal especially to organic electronic device applications where surface modification can play a critical role.

Metal chalcogenide compounds have attracted interest as materials for next-generation semiconductors, catalysts, and device architectures. Hybrid compounds containing both a metal chalcogenide architecture and a supporting organic lattice combine the interesting structural and electronic properties of the material class with a configurable hybrid component that can lead to a wide range of tailorable materials. However, many of the methods available for preparing inorganic coordination polymers in this class require specialized solution-phase chemical preparations that are incompatible with solid-state fabrication techniques. Here, we prepare metal-organic chalcogenolates (MOChas) of copper, indium, lead, and tin from benzeneselenol or benzenethiol directly from the organochalcogen and corresponding metal in a tube furnace at a relatively modest temperature. Scanning electron microscopy and X-ray diffraction confirmed the conversion of the precursors to crystalline MOChas. X-ray photoelectron spectroscopy was used to investigate the chemical bonding for each of the materials and provides insight into the elemental composition of the synthesized compounds. This straightforward approach for preparing crystalline hybrid materials may be generalizable for the preparation of a wide variety of coordination compounds and complexes in form factors useful for subsequent development of device architectures.

Silver metal exposed to the atmosphere corrodes and becomes tarnished as a result of oxidation and precipitation of the metal as an insoluble salt. Tarnish has so poor a reputation that the word itself connotes corruption and disrespectability; however, tarnishing is a facile synthetic approach for preparing thin metal-sulfide films on silver or copper metal that might be exploited to prepare more elaborate materials with desirable optoelectronic properties. In this work, we prepare luminescent semiconducting thin films of mithrene, a metal-organic chalcogenolate assembly, by replacing the tarnish-causing atmospheric sulfur source with diphenyl diselenide. Mithrene, or silver benzeneselenolate [AgSePh]∞, is a crystalline solid that contains both an organic supramolecular phase and a two-dimensional inorganic coordination polymer phase. This compound gradually accumulates as the sole product of silver metal corrosion. The chemical reaction is carried out on metallic silver thin films and yields crystalline films with thicknesses ranging from 5 to 100 nm. We use the large-area films (>6 cm2) afforded by this method to measure the optical properties of this compound. The mild-temperature, wafer-scale processing of hybrid chalcogenolate thin films may prove useful in the application of hybrid organic-inorganic materials in semiconductor devices and hierarchical architectures.