Femtosecond Mamyshev fiber oscillator started by a passively Q-switched microchip laser.

A femtosecond Mamyshev fiber oscillator in normal dispersion mode at 1 µm was started reliably and safely by an inexpensive diode-pumped passively Q-switched monolithic microchip laser emitting 300-ps pulses. Four-wave mixing spectral broadening is shown to play a pivotal role in starting the Mamyshev oscillator, owing to the random short and intense temporal fluctuations allowed by its ∼10-nm bandwidth. Systematic studies of the starting dynamics show that a success rate of 100% of the attempts is achieved with modest seed energy, as low as ∼30 nJ from the sub-nanosecond laser, corresponding to ∼100 pJ for the total four-wave mixing signal required to start the oscillation.

Strategy for primary prevention of non-communicable diseases (NCD) and mitigation of climate change in Italy.

This paper derives from a document commissioned in 2019 by the Italian Minister of Health, and outlines a general strategy for primary prevention of non-communicable diseases in Italy, with a special focus on cobenefits of climate change mitigation. Given that action against climate change is primarily taken via energy choices, limiting the use of fossil fuels and promoting renewable sources, an effective strategy is one in which interventions are designed to prevent diseases and jointly mitigate climate change, the so-called cobenefits. For policies capable of producing relevant co-benefits we focus on three categories of interventions, urban planning, diet and transport that are of special importance. For example, policies promoting active transport (cycling, walking) have the triple effect of mitigating greenhouse gas emissions, preventing diseases related to atmospheric pollution, and increasing physical activity, thus preventing obesity and diabetes.In particular, we propose that for 2025 the following goals are achieved: reduce the prevalence of smokers by 30%, with particular emphasis on young people; reduce the prevalence of childhood obesity by 20%; reduce the proportion of calories obtained from ultraprocessed foods by 20%; reduce the consumption of alcohol by 10%; reduce the consumption of salt by 30%; reduce the consumption of sugary drinks by 20%; reduce the average consumption of meat by 20%; increase the weekly hours of exercise by 10%. The aim is to complement individual health promotion with structural policies (such as urban planning, taxation and incentives) which render the former more effective and result in a reduction in inequality. We strongly encourage the inclusion of primary prevention in all policies, in light of the described cobenefits. Italy's role as the cohost of the 2020 (now 2021) UN climate negotiations (COP26) presents the opportunity for international leadership in addressing health as an integral component of the response to climate change.

Special Report: The Biology of Inequalities in Health: The Lifepath Consortium.

Funded by the European Commission Horizon 2020 programme, the Lifepath research consortium aimed to investigate the effects of socioeconomic inequalities on the biology of healthy aging. The main research questions included the impact of inequalities on health, the role of behavioral and other risk factors, the underlying biological mechanisms, the efficacy of selected policies, and the general implications of our findings for theories and policies. The project adopted a life-course and comparative approach, considering lifetime effects from childhood and adulthood, and pooled data on up to 1.7 million participants of longitudinal cohort studies from Europe, USA, and Australia. These data showed that socioeconomic circumstances predicted mortality and functional decline as strongly as established risk factors currently targeted by global prevention programmes. Analyses also looked at socioeconomically patterned biological markers, allostatic load, and DNA methylation using richly phenotyped cohorts, unraveling their association with aging processes across the life-course. Lifepath studies suggest that socioeconomic circumstances are embedded in our biology from the outset-i.e., disadvantage influences biological systems from molecules to organs. Our findings have important implications for policy, suggesting that (a) intervening on unfavorable socioeconomic conditions is complementary and as important as targeting well-known risk factors, such as tobacco and alcohol consumption, low fruit and vegetable intake, obesity and a sedentary lifestyle, and that (b) effects of preventive interventions in early life integrate interventions in adulthood. The report has an executive summary that refers to the different sections of the main paper.

Nd:YVO4 amplifier for ultrafast low-power lasers.

An Nd:YVO4 amplifier consisting of two modules end pumped at 808 nm at 30 W total absorbed power has been designed for efficient, diffraction-limited amplification of ultrafast pulses from low-power seeders. We investigated amplification with a 50 mW, 7 ps Nd:YVO4 oscillator, a 2 mW, 15 ps Yb fiber laser, and a 30 mW, 300 fs Nd:glass laser. Output power as high as 9.5 W with 8 ps pulses was achieved with the 250 MHz vanadate seeder, whereas the 20 MHz fiber laser was amplified to 6 W. The femtosecond seeder allowed extracting Fourier-limited 4 ps pulses at 7 W output power. To our knowledge, these are the shortest pulses from any Nd:YVO4 laser device with at least 7 W output power. This suggests a novel approach to exploit the gain bandwidth of vanadate amplifiers with high output power levels. Such amplifier technology promises to offer an interesting alternative to high-power thin disk oscillators at few picoseconds duration, as well as to regenerative amplifiers with low-repetition-rate fiber seeders.

Laser system generating 250-mJ bunches of 5-GHz repetition rate, 12-ps pulses.

We report on a high-energy solid-state laser based on a master-oscillator power-amplifier system seeded by a 5-GHz repetition-rate mode-locked oscillator, aimed at the excitation of the dynamic Casimir effect by optically modulating a microwave resonator. Solid-state amplifiers provide up to 250 mJ at 1064 nm in a 500-ns (macro-)pulse envelope containing 12-ps (micro-)pulses, with a macro/micropulse format and energy resembling that of near-infrared free-electron lasers. Efficient second-harmonic conversion allowed synchronous pumping of an optical parametric oscillator, obtaining up to 40 mJ in the range 750-850 nm.

Femtosecond Nd:glass oscillator operating in normal dispersion regime.

A diode-pumped, prismless Nd:glass laser oscillator, mode-locked by a semiconductor saturable absorber, was stabilized against self-Q-switching by using a phase-mismatched second harmonic crystal. Furthermore, negative-index cascaded second-order nonlinearity provided the soliton shaping mechanism with normal intracavity dispersion. Nearly Fourier-limited pulses as short as 520 fs were obtained.

High-gain diode-pumped amplifier for generation of microjoule-level picosecond pulses.

A diode-pumped single-pass amplifier system relying on two grazing-incidence Nd:YVO(4) slabs was developed to increase the energy of low-repetition-rate pulses from a decimated low-power cw mode-locked oscillator. Single-pass unsaturated gain up to 1.3x10(5) was achieved, and amplified pulses of 10-muJ energy and 8.0-ps duration were obtained. Efficient second harmonic generation (SHG) at 532 nm was achieved, as well as traveling-wave parametric conversion in the range 770-1020 nm (signal) and 1110-1720 nm (idler).