High-power broadband laser source tunable from 3.0 um to 4.4 um based on a femtosecond Yb:fiber oscillator

We describe a tunable broadband mid-infrared laser source based on difference-frequency mixing of a 100 MHz femtosecond Yb:fiber laser oscillator and a Raman-shifted soliton generated with the same laser. The resulting light is tunable over 3.0 um to 4.4 um, with a FWHM bandwidth of 170 nm and maximum average output power up to 125 mW. The noise and coherence properties of this source are also investigated and described.Comment: To appear in Optics Letter

Factorization of Numbers with the temporal Talbot effect: Optical implementation by a sequence of shaped ultrashort pulses

We report on the successful operation of an analogue computer designed to factor numbers. Our device relies solely on the interference of classical light and brings together the field of ultrashort laser pulses with number theory. Indeed, the frequency component of the electric field corresponding to a sequence of appropriately shaped femtosecond pulses is determined by a Gauss sum which allows us to find the factors of a number

Switching dynamics of spatial solitary wave pixels

Separatrices and scaling laws in the switching dynamics of spatial solitary wave pixels are investigated. We show that the dynamics in the full model are similar to those in the plane-wave limit. Switching features may be indicated and explained by the motion of the (complex) solitary wave amplitude in the phase plane. We report generalization, into the domain of transverse effects, of the pulse area theorem for the switching process and a logarithmic law for the transient dynamics. We also consider, for what is the first time to our knowledge, phase-encoded address of solitary pixels and find that a near-square-wave temporal switching pattern is permitted without (transverse) cross switching

Homodyne detection for atmosphere channels

We give a systematic theoretical description of homodyne detection in the case where both the signal and the local oscillator pass through the turbulent atmosphere. Imperfect knowledge of the local-oscillator amplitude is effectively included in a noisy density operator, leading to postprocessing noise. Alternatively, we propose a technique with monitored transmission coefficient of the atmosphere, which is free of postprocessing noise.Comment: 9 pages, 5 figure

Toward Global Quantum Communication: Beam Wandering Preserves Nonclassicality

Tap-proof long-distance quantum communication requires a deep understanding of the strong losses in transmission channels. Here we provide a rigorous treatment of the effects of beam wandering, one of the leading disturbances in atmospheric channels, on the quantum properties of light. From first principles we derive the probability distribution of the beam transmissivity, with the aim to completely characterize the quantum state of light. It turns out that beam wandering may preserve nonclassical effects, such as entanglement, quadrature and photon number squeezing, much better than a standard attenuating channel of the same losses.Comment: published versio

Leading Order Temporal Asymptotics of the Modified Non-Linear Schrodinger Equation: Solitonless Sector

Using the matrix Riemann-Hilbert factorisation approach for non-linear evolution equations (NLEEs) integrable in the sense of the inverse scattering method, we obtain, in the solitonless sector, the leading-order asymptotics as $t$ tends to plus and minus infinity of the solution to the Cauchy initial-value problem for the modified non-linear Schrodinger equation: also obtained are analogous results for two gauge-equivalent NLEEs; in particular, the derivative non-linear Schrodinger equation.Comment: 29 pages, 5 figures, LaTeX, revised version of the original submission, to be published in Inverse Problem

Modelling fatigue in manual and robot-assisted work for operator 5.0

Occupational Applications: Fatigue, and many other human performance factors, impact worker wellbeing, and thus production quality and efficiency. Adopting the Industry 5.0 perspective, we propose that integrating human performance models into wider industrial system models can improve modeling accuracy and lead to superior outcomes. Integrating our Worker Fatigue Model as part of their industrial system architect model allowed Airbus, a leading aircraft manufacturer, to more accurately predict system performance as a function of the workforce makeup, which could be a combination of human workers and robots, or a combination of highly experienced and less experienced workers. Our approach demonstrates the importance and value of including human performance models in trade studies for introducing robots on the shop floor, and can be used to include various aspects of human performance in industrial system models to address specific task requirements or different levels of automation. Technical Abstract: Rationale: The advent of Industry 5.0 places a heightened focus on enhancing worker wellbeing during the digital transformation of factories. System models that ignore human workers yield suboptimal results in product design and system improvement.Purpose: In the aircraft industry, worker workload is of primary concern as most tasks are performed manually, leading to general fatigue and musculoskeletal disorders. Robot assistance could improve quality, efficiency and relieve workers from fatigue. To demonstrate the feasibility and value of integrating human performance models in system design at Airbus, a Worker Fatigue Model was developed, focusing on the effects of (1) automation (manual vs semi-automated), and (2) workforce makeup (various ratios of high-skilled to low-skilled workers). Our ultimate goal was to inform the development of effective policies and strategies for human-technology integration in Industry 5.0.Methods: We developed the Worker Fatigue Model by adapting existing fatigue models for workers in industrial environments and by considering worker characteristics, tasks, and the presence or absence of robot-assistance. Two different scenarios were simulated (fully manual and semi-automated), with input variables such as worker skill, age, and motivation, and output variables including overall fatigue and error probabilities were evaluated. The Worker Fatigue Model was integrated into the Airbus system model to conduct trade studies based on workforce characteristics.Results: Our findings revealed that the composition of the workforce (i.e., various ratios of high-skilled to low-skilled workers), alongside specific manufacturing technologies, significantly reduced worker fatigue, especially with higher ratios of high-skilled workers, and improved overall industrial system performance.Conclusions: Although applying our Worker Fatigue Model effectively demonstrated the feasibility and value of integrating human factors into early industrial system design, it remains a work in progress. Future work will aim to accurately represent the workload of human workers, including operational costs, when implementing robot assistance

Mitochondrial and plastidial COG0354 proteins have folate-dependent functions in iron–sulphur cluster metabolism

COG0354 proteins have been implicated in synthesis or repair of iron/sulfur (Fe/S) clusters in all domains of life, and those of bacteria, animals, and protists have been shown to require a tetrahydrofolate to function. Two COG0354 proteins were identified in Arabidopsis and many other plants, one (At4g12130) related to those of α-proteobacteria and predicted to be mitochondrial, the other (At1g60990) related to those of cyanobacteria and predicted to be plastidial. Grasses and poplar appear to lack the latter. The predicted subcellular locations of the Arabidopsis proteins were validated by in vitro import assays with purified pea organelles and by targeting assays in Arabidopsis and tobacco protoplasts using green fluorescent protein fusions. The At4g12130 protein was shown to be expressed mainly in flowers, siliques, and seeds, whereas the At1g60990 protein was expressed mainly in young leaves. The folate dependence of both Arabidopsis proteins was established by functional complementation of an Escherichia coli COG0354 (ygfZ) deletant; both plant genes restored in vivo activity of the Fe/S enzyme MiaB but restoration was abrogated when folates were eliminated by deleting folP. Insertional inactivation of At4g12130 was embryo lethal; this phenotype was reversed by genetic complementation of the mutant. These data establish that COG0354 proteins have a folate-dependent function in mitochondria and plastids, and that the mitochondrial protein is essential. That plants retain mitochondrial and plastidial COG0354 proteins with distinct phylogenetic origins emphasizes how deeply the extant Fe/S cluster assembly machinery still reflects the ancient endosymbioses that gave rise to plants

Self starting additive pulse modelocking of a Nd:LMA laser

A Ti:sapphire-pumped Nd:LMA laser has been passively mode locked by using additive-pulse mode locking, which generates 600-fs-duration pulses at 1.054-µm. The wavelength, pulse duration, and long-term stability of the laser make it eminently suitable as a front-end oscillator of a high-power, chirped-pulse amplifier experiment based on 1.053-µm amplification in Nd:phosphate glass