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Dissipative quadratic solitons (DQSs), enabled by nonlinearity engineering through cascaded quadratic processes, have remained a central theoretical prediction in nonlinear optics since their proposal in 1997. Despite their predicted ultralow operational thresholds, remarkable tunability, and potential for spectral extension into unconventional wavelengths, their experimental realization has remained elusive. Here, we demonstrate bright, dual-color DQS generation in the normal dispersion regime, in strong agreement with the proposed theoretical framework. Furthermore, by simply adjusting the nonlinear crystal temperature - without any structural modification - we reverse the sign of the effective nonlinearity and switch from bright DQS to platicon generation in situ. This work not only advances the fundamental understanding of dissipative solitons but also establishes a practical pathway for ultralow-threshold frequency comb generation at unconventional wavelengths, with broad implications for applications such as atomic clocks, optical coherence tomography, and astrocombs. In this work, the authors demonstrate nonlinearity-engineered dissipative quadratic solitons (DQS) for the first time. Moreover, they achieve an in-situ sign reversal of the effective nonlinearity, enabling a transition from bright DQS to platicon generation without requiring any dispersion engineering.

Dissipative Kerr soliton (DKS) microcomb has emerged as an enabling technology that revolutionizes a wide range of applications in both basic science and technological innovation. Reliable turnkey operation with sub-optical-cycle and sub-femtosecond timing jitter is key to the success of many intriguing microcomb applications at the intersection of ultrafast optics and microwave electronics. Here we propose an approach and demonstrate the first turnkey Brillouin-DKS frequency comb to the best of our knowledge. Our microresonator-filtered laser design offers essential benefits, including phase insensitivity, self-healing capability, deterministic selection of the DKS state, and access to the ultralow noise comb state. The demonstrated turnkey Brillouin-DKS frequency comb achieves a fundamental comb linewidth of 100 mHz and DKS timing jitter of 1 femtosecond for averaging times up to 56 μs. The approach is universal and generalizable to various device platforms for user-friendly and field-deployable comb devices. Here the authors demonstrate a universal approach to achieve turnkey dissipative Kerr soliton (DKS) frequency comb. Phase insensitivity, self-healing capability, deterministic selection of DKS state, and access to ultralow noise are all successfully accomplished.

To better understand the origin of microplastics in municipal drinking water, we evaluated 50 mL water samples from different stages of the City of Rochester’s drinking water production and transport route, from Hemlock Lake to the University of Rochester. We directly filtered samples using silicon nitride nanomembrane filters with precisely patterned slit-shaped pores, capturing many of the smallest particulates (<20 µm) that could be absorbed by the human body. We employed machine learning algorithms to quantify the shapes and quantity of debris at different stages of the water transport process, while automatically segregating out fibrous structures from particulate. Particulate concentrations ranged from 13 to 720 particles/mL at different stages of the water transport process and fibrous pollution ranged from 0.4 to 8.3 fibers/mL. A subset of the debris (0.2–8.6%) stained positively with Nile red dye which identifies them as hydrophobic polymers. Further spectroscopic analysis also indicated the presence of many non-plastic particulates, including rust, silicates, and calcium scale. While water leaving the Hemlock Lake facility is mostly devoid of debris, transport through many miles of piping results in the entrainment of a significant amount of debris, including plastics, although in-route reservoirs and end-stage filtration serve to reduce these concentrations.

Ultrafast optics is driven by a myriad of complex nonlinear dynamics. The ubiquitous presence of governing equations in the form of partial integro-differential equations (PIDE) necessitates the need for advanced computational tools to understand the underlying physical mechanisms. From the experimental perspective, signal-to-noise ratio and availability of measurable data, accounts for a bottle neck in numerical and data-driven modeling methods. In this paper we extend the application of the physics informed neural network (PINN) architecture to include prior knowledge in both the physical and Fourier domain. We demonstrate our Fourier Domain PINN (FD-PINN) in two distinct forms. The Continuous time FD-PINN is used to predict accurate solutions to the Generalized Pulse Propagation Equation, which includes the complete delayed nonlinear response, in the data-starved and noisy regime. We extend the architecture to the Discrete time FD-PINN to recover the delayed-response physics from spatially separated measurement points. We conducted the first systematic study of the effect of SNR on the spatiotemporal field prediction as well as physics discovery. Our architecture ensures high fidelity predictive modeling and hidden physics recovery for applications such as image reconstruction, pulse characterization and shaping, as well as hidden parameter discovery. The benefits of the FD-PINN for ultrafast nonlinear optics make it immediately experimentally deployable. FD-PINN represents the next generation of tools to study optical phenomena both through modeling and measurements for both forward and inverse problems.

Researchers estimate that between television, radio, the internet, email, and social media, the average person receives the equivalent of 174 newspapers worth of data every day. The financial advisors my firm works with, for example, tell us that they build such good rapport with their seminar attendees before the event occurs because of the way they're featured on the event landing page. Becoming more transparent through digital marketing can greatly improve a company's efficiency by spending less time talking around product limitations and sidestepping customers' concerns.

Der Autor verfolgt mit dieser Arbeit zwei Ziele: 1. einen Kommentar zu den Berichten von Gorjanović-Kramberger über die Handknochen von Krapina und 2. das erste vollständige Inventar dieser Knochen zu geben. Eingeschlossen sind Maße — und zwar die von Gorjanović-Kramberger und die des Autors — sowie die Ergebnisse von Mahalanobis’ D2-Analysen auf der Basis dieser Maße.

In this paper – the revised text of a public lecture given in Athens on 23 February 1989 – the author reviews both the historical and anatomical evidence for identifying the occupants of the royal tombs at Vergina as: Tomb I: not known; Tomb II: Philip II and either Cleopatra or Meda; Tomb III: Alexander IV. The case for Philip III Arrhidaios and Eurydice in Tomb II is shown to be anthropologically weak. The paper also includes a catalogue of the human remains from Tomb II antechamber (Cleopatra or Meda) and Tomb III (Alexander IV). The arrival of cremation in Greece, and both Homeric and later Macedonian attitudes to the rite are also discussed. The general conclusion is that cremations are a valuable source of biological and archaeological information.

Death may be the great leveller, but some families can mark the event more spectacularly than others. In an attempt to set the royal burials at Vergina into some form of mortuary context, the cremated remains from three rich, non-royal 4th-century Macedonian tombs – Nea Mihaniona II and III and Derveni Beta – were studied with an eye on both biology and mortuary practices. This investigation showed that: (i) a neonate cremated and buried with its mother can survive both events remarkably well, with important consequences for the Vergina debate; (ii) the Derveni crater contained two individuals; (iii) the Nea Mihaniona, Derveni Beta, Vergina II antechamber, Vergina III and Phoinikas (report in preparation) cremations form a homogeneous group in terms of fragment size and weight. This sets them midway between (a) their far less substantial Dark Age forebears and (b) the unique whole cremated skeleton from the main chamber of Vergina Tomb II.