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Abstract Harmonic generation is a result of a strong non-linear interaction between light and matter. It is a key technology for optics, as it allows the conversion of optical signals to higher frequencies. Owing to its intrinsically large and electrically tunable non-linear optical response, graphene has been used for high harmonic generation but, until now, only at frequencies

The integration of nano-molecules into microelectronic circuitry is challenging. Here, the authors provide a scalable method for contacting a self-assembled monolayer of nanoparticles with a single layer of graphene that produces single-electron effects, in the form of a Coulomb staircase, with a yield of at least 70%.

Optical receivers based on graphene still suffer from low responsivity. Here, the authors integrate a photo-thermoelectric graphene photodetector with a Si micro-ring resonator, and obtain a voltage responsivity ~ 90 V/W and a reduction of energy-per-bit consumption, enabling performance on par with mature semiconductor technology.

The main limitation to the areal storage density of hard disk drives (HDDs) is the thickness of carbon overcoats protecting the disk media. Here,

Here, the authors report optoelectronic mixing up to 67 GHz using high-frequency back-gated graphene field effect transistors (GFETs). These devices mix an electrical signal injected into the GFET gate and a modulated optical signal onto a single layer graphene channel.

The exciton–phonon coupling (EXPC) affects the opto-electronic properties of atomically thin semiconductors. Here, the authors develop two-dimensional micro-spectroscopy to determine the EXPC of monolayer MoSe2.

The primary stages of carrier relaxation in atomically thin transition metal dichalcogenides are hardly accessible due to their fast timescales. Here, the authors measure the first stages of carrier–phonon interaction in monolayer WSe2 via a series of periodic maxima in the hot photoluminescence intensity, assigned to phonon cascades.

Laser-based lighting typically relies on wavelength conversion materials that reduce efficiency. The authors present a 3D boron nitride hollow-tube based foam structure that acts as a broadband diffuser with engineered disorder for conversionless white light generation from laser-diode light sources

Coherent anti-Stokes Raman Scattering (CARS) accesses the vibrational properties of a material via nonlinear four-wave mixing (FWM); CARS in graphene has not been observed to date despite its high nonlinear third-order susceptibility. Here, the authors devised a FWM scheme to perform stimulated Raman spectroscopy in single and multi-layer graphene through CARS.

Atomically-clean interfaces are required in heterostructures. Here, authors report a method for fast and parallel removal of contaminants from fully-formed heterostructures, including sample intentionally exposed to polymers and solvent, achieving room temperature mobility over 180,000 cm2/Vs for graphene.

Multi-exciton states may emerge in atomically thin transition metal dichalcogenides as a result of strong many-body interactions. Here, the authors report experimental evidence of four- and five-particle biexciton complexes in monolayer WSe2 and their electrical control.

Non-equilibrium ultrafast processes in graphene entail relaxation pathways involving electron–electron and electron–phonon scattering events. Here, the authors probe graphene optical phonons at high electronic temperatures by means of Raman spectroscopy under pulsed excitation

Harmonic generation is a nonlinear optical process occurring in a variety of materials; the higher orders generation is generally less efficient than lower orders. Here, the authors report that the third-harmonic is thirty times stronger than the second-harmonic in monolayer MoS2.

Graphene shows promise for saturable absorption, a key property for ultrafast lasing, yet graphene saturable absorbers operating in the terahertz region suffer from low absorption modulation. Here, the authors report terahertz saturable absorbers based on inkjet printed graphene with 80% transparency modulation.

Quantum emitters have been recently isolated in 2D materials, yet their spatial controllability remains an open challenge. Here, the authors devise a method to create arrays of quantum emitters in WSe2 and WS2, by taking advantage of the strain distribution induced by a nanopatterned silica substrate.

Unconventional superconductivity may be triggered when graphene is deposited on a high temperature superconductor. Here, Di Bernardoet al. observe spectroscopic evidence for p-wave superconductivity in single layer graphene on an electron-doped cuprate superconductor.

There is emerging interest in photodetectors in the mid-infrared driven by increasing need to monitor the environment for security and healthcare purposes. Sassiet al. show a thermal photodetector, based on the coupling between graphene and a pyroelectric crystal, which shows high temperature sensitivity.

Impurities and vacancies are commonly found within the crystalline lattice of transition metal dichalcogenides, however they are usually seen as detrimental for their optical properties. Here, the authors demonstrate that sulfur vacancies in MoS2can give rise to a near-infrared emission peak.

Atomically thin transition metal dichalcogenides hold promise as scalable single-photon sources. Here, the authors demonstrate all-electrical, single-photon generation in tungsten disulphide and diselenide, achieving charge injection into the layers, containing quantum emitters.

Photochemical isomerisation can engender large conformational rearrangements, giving rise to switchable physical and electronic properties. Here, the authors use azo-benzene derivatives as addressable surfactants to facilitate the exfoliation of graphene and provide light activated modulation.

Nature Communications 8: Article number: 14024 (2017); Published: 19 January 2017; Updated: 1 March 2017 The present address for U. Sassi is incorrect in this Article. This author does not have a present address. The correct full affiliation details for this author are given below: Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, UK.

Hepatitis C virus infection (HCV) represents a unique model to characterize, from early to late stages of infection, the T cell differentiation process leading to exhaustion of human CD8+ T cells. Here we show that in early HCV infection, exhaustion-committed virus-specific CD8+ T cells display a marked upregulation of transcription associated with impaired glycolytic and mitochondrial functions, that are linked to enhanced ataxia-telangiectasia mutated (ATM) and p53 signaling. After evolution to chronic infection, exhaustion of HCV-specific T cell responses is instead characterized by a broad gene downregulation associated with a wide metabolic and anti-viral function impairment, which can be rescued by histone methyltransferase inhibitors. These results have implications not only for treatment of HCV-positive patients not responding to last-generation antivirals, but also for other chronic pathologies associated with T cell dysfunction, including cancer.

Plants have adapted to the diurnal light-dark cycle by establishing elaborate transcriptional programs that coordinate many metabolic, physiological, and developmental responses to the external environment. These transcriptional programs have been studied in only a few species, and their function and conservation across algae and plants is currently unknown. We performed a comparative transcriptome analysis of the diurnal cycle of nine members of Archaeplastida, and we observed that, despite large phylogenetic distances and dramatic differences in morphology and lifestyle, diurnal transcriptional programs of these organisms are similar. Expression of genes related to cell division and the majority of biological pathways depends on the time of day in unicellular algae but we did not observe such patterns at the tissue level in multicellular land plants. Hence, our study provides evidence for the universality of diurnal gene expression and elucidates its evolutionary history among different photosynthetic eukaryotes.

The structural defects in two-dimensional transition metal dichalcogenides, including point defects, dislocations and grain boundaries, are scarcely considered regarding their potential to manipulate the electrical and optical properties of this class of materials, notwithstanding the significant advances already made. Indeed, impurities and vacancies may influence the exciton population, create disorder-induced localization, as well as modify the electrical behaviour of the material. Here we report on the experimental evidence, confirmed by ab initio calculations, that sulfur vacancies give rise to a novel near-infrared emission peak around 0.75 eV in exfoliated MoS 2 flakes. In addition, we demonstrate an excess of sulfur vacancies at the flake's edges by means of cathodoluminescence mapping, aberration-corrected transmission electron microscopy imaging and electron energy loss analyses. Moreover, we show that ripplocations, extended line defects peculiar to this material, broaden and redshift the MoS 2 indirect bandgap emission.

Wave mixing inside optical resonators, while experiencing a large enhancement of the nonlinear interaction efficiency, suffers from strong bandwidth constraints, preventing its practical exploitation for processing broad-band signals. Here we show that such limits are overcome by the new concept of travelling-wave resonant four-wave mixing (FWM). This approach combines the efficiency enhancement provided by resonant propagation with a wide-band conversion process. Compared with conventional FWM in bare waveguides, it exhibits higher robustness against chromatic dispersion and propagation loss, while preserving transparency to modulation formats. Travelling-wave resonant FWM has been demonstrated in silicon-coupled ring resonators and was exploited to realize a 630-μm-long wavelength converter operating over a wavelength range wider than 60 nm and with 28-dB gain with respect to a bare waveguide of the same physical length. Full compatibility of the travelling-wave resonant FWM with optical signal processing applications has been demonstrated through signal retiming and reshaping at 10 Gb s(-1).