We present a laser-based neutron source that produces 1.8 × 10^5 neutrons/s with a conversion rate of 7.8 × 10^5 neutrons/J. Laser pulses of 12 fs and 23 mJ were focused onto a 430-nm-thick heavy water liquid sheet at a 10 Hz repetition rate. The resulting peak intensity of 4 × 10^18 W/cm^2 accelerated deuterium ions from the target rear side to a kinetic energy of 1 MeV. This deuteron beam induced ^2H(d,n)^3He fusion reactions in a deuterated polyethylene target, producing fast neutrons. The neutron yield was measured using two independent detection systems: the LILITH time-of-flight spectrometer, consisting of eight plastic scintillators covering nearly 180^∘, and a calibrated bubble detector spectrometer. The neutron yield per laser shot is 35 times higher than that recently achieved by lasers with comparable pulse energies, while the conversion rate is the highest ever achieved by continuously operating, sub-100 fs lasers. The generated neutrons are emitted from an area of 0.65 cm^2 corresponding to the deuteron beam spot on the catcher. Their angular distribution is peaked in forward and backward directions in agreement with the literature data on the angular distribution of ^2H(d,n)^3He reaction. The system operated continuously for several hours per day with an unprecedented stability of 5

Laser-driven deuterons generate neutrons with a mean energy of 2.5 MeV, through the 2H(d,n) fusion reaction in a deuterated polyethylene (dPE) tablet. The deuterium ions are accelerated by 12 fs, 21 mJ laser pulses interacting with a 0.2 µm thin dPE foil at a peak intensity of 1018 W/cm2. The laser was operated at 1 Hz repetition rate in bursts of 75 shots. The interaction was characterized and recorded for each laser shot. The ion spectra were measured in the forward and backward directions by Thomson ion spectrometers. Neutron events were detected by a time-of-flight (ToF) system consisting of four plastic scintillators positioned at various angles around the experimental chamber. The maximum cut-off energy of the forward accelerated protons and deuterons was close to 1.4 MeV and 1 MeV, while the mean values are 428 ± 63 keV and 433 ± 80 keV, respectively. Analysis of ToF distributions from 3128 shots resulted in an average yield of 1142 ± 59 neutrons per shot in the energy range of 1.5-4 MeV. The energy distribution of forward-directed neutrons peaks between 3 and 3.5 MeV. Angular dependence analysis showed a perpendicular minimum and a maximum along the deuteron beam, consistent with the expected distribution from the literature and our simulation results.

We report on the most recent progress of the few-cycle lasers of ELI-ALPS user facility, operating in the 100W average power regime, while peak powers and repetition rates range from 0.1TW at 100kHz up to PW at 10Hz.

The SYLOS 1kHz OPCPA systems are the main drivers for attosecond and particle secondary sources at ELI-ALPS. Over the recent years, several upgrades increased their overall performance for the benefit of external user community.

Generation of intense, isolated attosecond pulses [1] is the main motivation for the development of laser systems which are producing few-cycle, TW-level pulses [2-5]. The ELI-ALPS Single Cycle Laser (SYLOS) aims to provide 20 TW single cycle pulses at 1 kHz repetition rate [6]. Due to the requirements for stability and high average power the most promising approach for generating mJ-level, few-cycle pulses is noncollinear optical parametric chirped pulse amplification (NOPCPA) [2-5]. BBO and LBO are the two most favoured nonlinear materials in the visible and near-infrared spectral range, due to their broad gain bandwidth and high damage threshold. It was demonstrated that BBO and LBO can support 5.5 fs [4] and 7 fs [3] pulse durations respectively when 450 nm [4] and 515 nm [3] pumping was used. Even shorter, sub-5 fs pulse durations can be achieved by utilizing two-color pumping, that is, the second- and third-harmonic of a Nd:YAG pump laser in subsequent amplifier stages [2]. The latter solution is the most promising, however at 1 kHz repetition rate there is a risk of optics degradation due to high average power UV light.

A 10 kHz KTA-based OPCPA system was numerically investigated with exceptionally short 43 mJ signal and 10 mJ idler output pulses. Thermal limitations of the amplifier were thoroughly analyzed with special care on power stages.

In the past decade ultrafast mid-IR laser sources have experienced fast growing, due to the fact that many applications benefit from long wavelength driving pulses. For instance the cut-off energy for high harmonic generation can be extended to the keV range [1], however the conversion efficiency varies as ~λ -6 [2]. Consequently, the generation of few-tens of mJ mid-IR driving pulses is essential together with high repetition rate in order to compensate the low efficiency in strong field experiments. Commercially available ytterbium-based thin-disk pump lasers are now capable of delivering 200 mJ pulses at 1 kHz repetition rate [3], and it is expected that the average power of these pump lasers will be promoted to the 2 kW range soon. These are ideal sources for pumping mid-IR chirped pulse optical parametric amplifier (OPCPA) systems, thus making it possible to produce multi-mJ pulses in the mid-IR range beyond 1 kHz repetition rate.

We demonstrate an OPCPA driven thin plate compression in the mid-infrared region at 100 kHz with 7 W average output power. The resulting pulses are close to two cycle long and CEP stable.

ELI-ALPS 1kHz SYLOS laser aims to deliver 5.5TW, two-cycle pulses for attosecond pulse and electron beam generation. In this study, broadband NOPCPA schemes were examined based on spectral multiplexing in different BBO and LBO configurations.