Visible supercontinuum generation controlled by intermodal four-wave mixing in micro-structured fibre

International audienceWe present an experimental and numerical study of supercontinuum generation extended in the visible part of the spectrum by using a selective optical coupling of the pump wave in the largely anomalous dispersion regime. The broadband frequency generation is induced by an initial four-wave mixing process that converts the pump wave at 1064 nm into 831 nm anti-Stokes and 1478 nm Stokes wavelengths. Phase matching is ensured on such a large frequency shift thanks to a microstructured multimodal fiber with a specific design. Continuum generation is therefore enhanced around the two generated sideband

Passively mode-locked diode-pumped Nd:YVO4 oscillator operating at ultra-low repetition rate

We demonstrate the operation of an ultra low repetition rate, high peak power, picosecond diode pumped Nd:YVO4 passively mode locked laser oscillator. Repetition rates even below 1 MHz were achieved with the use of a new design multiple-pass cavity and a semiconductor saturable absorber. Long term stable operation at 1.2 MHz, pulse duration of 16.3 ps and average output power of 470 mW corresponding to 24 KW peak power pulses is reported. This is, to our knowledge, the lowest repetition rate high peak power pulses ever generated directly from a picosecond laser resonator without cavity dumping

Zettawatt-Exawatt Lasers and Their Applications in Ultrastrong-Field Physics: High Energy Front

Since its birth, the laser has been extraordinarily effective in the study and applications of laser-matter interaction at the atomic and molecular level and in the nonlinear optics of the bound electron. In its early life, the laser was associated with the physics of electron volts and of the chemical bond. Over the past fifteen years, however, we have seen a surge in our ability to produce high intensities, five to six orders of magnitude higher than was possible before. At these intensities, particles, electrons and protons, acquire kinetic energy in the mega-electron-volt range through interaction with intense laser fields. This opens a new age for the laser, the age of nonlinear relativistic optics coupling even with nuclear physics. We suggest a path to reach an extremely high-intensity level $10^{26-28}$W/cm$^2$ in the coming decade, much beyond the current and near future intensity regime $10^{23}$W/cm$^2$, taking advantage of the megajoule laser facilities. Such a laser at extreme high intensity could accelerate particles to frontiers of high energy, tera-electron-volt and peta-electron-volt, and would become a tool of fundamental physics encompassing particle physics, gravitational physics, nonlinear field theory, ultrahigh-pressure physics, astrophysics, and cosmology. We focus our attention on high-energy applications in particular and the possibility of merged reinforcement of high-energy physics and ultraintense laser.Comment: 25 pages. 1 figur

New Economy, Food, and Agriculture

Consumers are becoming increasingly more informed about food systems and are interested not only in healthy, safe, and tasty food but also sustainable production, animal welfare, climate changes, and food waste. Consumers are also more focused on changing their lifestyle related to improved health knowledge and nutrition education (Timmer 2005). Maxwell and Slater (2004) have proposed criteria to evaluate food systems, including nutrition and health, rights and influence, security, sustainability, equality, and social inclusion. The authors also point out that the primary international institutions in the food value chain are not only the Food and Agriculture Organization and World Health Organization but also United Nations Industrial Development Organization, International Labour Organization, and World Trade Organization. The emerging trends in the food system are features of the {\dq}new economy.{\dq} This term describes the outcome of the transition from production- and manufacturing-based economy to a service-based or post-industrial economy at the end of the twentieth century. The traditional production factors such as cheap labor, land, and raw materials lose their importance in generating profits and competitiveness. The key is understanding of food consumer demand, knowledge of food industry and agriculture employees based on creativity, and flexibility of processes of production

New Economy, Food, and Agriculture

Consumers are becoming increasingly more informed about food systems and are interested not only in healthy, safe, and tasty food but also sustainable production, animal welfare, climate changes, and food waste. Consumers are also more focused on changing their lifestyle related to improved health knowledge and nutrition education (Timmer 2005). Maxwell and Slater (2004) have proposed criteria to evaluate food systems, including nutrition and health, rights and influence, security, sustainability, equality, and social inclusion. The authors also point out that the primary international institutions in the food value chain are not only the Food and Agriculture Organization and World Health Organization but also United Nations Industrial Development Organization, International Labour Organization, and World Trade Organization. The emerging trends in the food system are features of the {\dq}new economy.{\dq} This term describes the outcome of the transition from production- and manufacturing-based economy to a service-based or post-industrial economy at the end of the twentieth century. The traditional production factors such as cheap labor, land, and raw materials lose their importance in generating profits and competitiveness. The key is understanding of food consumer demand, knowledge of food industry and agriculture employees based on creativity, and flexibility of processes of production

Technical Design Report EuroGammaS proposal for the ELI-NP Gamma beam System

The machine described in this document is an advanced Source of up to 20 MeV Gamma Rays based on Compton back-scattering, i.e. collision of an intense high power laser beam and a high brightness electron beam with maximum kinetic energy of about 720 MeV. Fully equipped with collimation and characterization systems, in order to generate, form and fully measure the physical characteristics of the produced Gamma Ray beam. The quality, i.e. phase space density, of the two colliding beams will be such that the emitted Gamma ray beam is characterized by energy tunability, spectral density, bandwidth, polarization, divergence and brilliance compatible with the requested performances of the ELI-NP user facility, to be built in Romania as the Nuclear Physics oriented Pillar of the European Extreme Light Infrastructure. This document illustrates the Technical Design finally produced by the EuroGammaS Collaboration, after a thorough investigation of the machine expected performances within the constraints imposed by the ELI-NP tender for the Gamma Beam System (ELI-NP-GBS), in terms of available budget, deadlines for machine completion and performance achievement, compatibility with lay-out and characteristics of the planned civil engineering

Future Ocean Observations to Connect Climate, Fisheries and Marine Ecosystems

Advances in ocean observing technologies and modeling provide the capacity to revolutionize the management of living marine resources. While traditional fisheries management approaches like single-species stock assessments are still common, a global effort is underway to adopt ecosystem-based fisheries management (EBFM) approaches. These approaches consider changes in the physical environment and interactions between ecosystem elements, including human uses, holistically. For example, integrated ecosystem assessments aim to synthesize a suite of observations (physical, biological, socioeconomic) and modeling platforms [ocean circulation models, ecological models, short-term forecasts, management strategy evaluations (MSEs)] to assess the current status and recent and future trends of ecosystem components. This information provides guidance for better management strategies. A common thread in EBFM approaches is the need for high-quality observations of ocean conditions, at scales that resolve critical physical-biological processes and are timely for management needs. Here we explore options for a future observing system that meets the needs of EBFM by (i) identifying observing needs for different user groups, (ii) reviewing relevant datasets and existing technologies, (iii) showcasing regional case studies, and (iv) recommending observational approaches required to implement EBFM. We recommend linking ocean observing within the context of Global Ocean Observing System (GOOS) and other regional ocean observing efforts with fisheries observations, new forecasting methods, and capacity development, in a comprehensive ocean observing framework