Stimulated Raman scattering (SRS) in plasma in a non-eigenmode regime is studied theoretically and numerically. Different from normal SRS with the eigen electrostatic mode excited, the non-eigenmode SRS is developed at plasma density $n_{e}>0.25n_{c}$ when the laser amplitude is larger than a certain threshold. To satisfy the phase-matching conditions of frequency and wavenumber, the excited electrostatic

We report on the successful demonstration of a 150 J nanosecond pulsed cryogenic gas cooled, diode-pumped multi-slab Yb:YAG laser operating at 1 Hz. To the best of our knowledge, this is the highest energy ever recorded for a diode-pumped laser system.

White-light continuum can be induced by the interaction of intense femtosecond laser pulses with condensed materials. By using two orthogonal polarizers, a self-induced birefringence of continuum is observed when focusing femtosecond laser pulses into bulk fused silica. That is, the generated white-light continuum is synchronously modulated anisotropically while propagating in fused silica. Time-resolved

We report the development of a stable high-average power X-ray source generated by the interaction of ultrashort laser pulses (35 fs, 1 mJ, 1 kHz) with a solid target in air. The achieved source stability, which is essential for the applications foreseen for these laser-driven plasma accelerators, is due to the combination of precise positioning of the target on focus and the development of a fast

We report on a compact and robust self-referenced optical frequency comb with a tunable repetition rate, generated by an all-polarization-maintaining (PM) mode-locked Er-doped fiber laser. The spacing between comb teeth can be tuned above 300 kHz at a repetition rate of 101 MHz. The repetition rate and the carrier–envelope offset of the laser are stabilized separately, and the relative residual phase

Experimental and simulation data [Moreau et al., Plasma Phys. Control. Fusion 62, 014013 (2019); Kaymak et al., Phys. Rev. Lett. 117, 035004 (2016)] indicate that self-generated magnetic fields play an important role in enhancing the flux and energy of relativistic electrons accelerated by ultra-intense laser pulse irradiation with nanostructured arrays. A fully relativistic analytical model for the

We report on mode-locked thulium-doped fiber lasers with high-energy nanosecond pulses, relying on the transmission in a semiconductor saturable absorber (SESA) and a carbon nanotube (CNTs-PVA) film separately. A section of an SMF–MMF–SMF structure multimode interferometer with a transmission peak wavelength of ∼2003 nm was used as a wavelength selector to fix the laser wavelength. When the SESA acted

The process of high energy electron acceleration along the surface of grating targets (GTs) that were irradiated by a relativistic, high-contrast laser pulse at an intensity $I=2.5\times 10^{20}~\text{W}/\text{cm}^{2}$ was studied. Our experimental results demonstrate that for a GT with a periodicity twice the laser wavelength, the surface electron flux is more intense for a laser incidence angle that

We demonstrated a high-power long-wave infrared laser based on a polarization beam coupling technique. An average output power at $8.3~\unicode[STIX]{x03BC}\text{m}$ of 7.0 W was achieved at a maximum available pump power of 107.6 W, corresponding to an optical-to-optical conversion of 6.5%. The coupling efficiency of the polarization coupling system was calculated to be approximately 97.2%. With idler

We address the power scaling issue in end-pumped laser rod amplifiers by studying, experimentally and numerically, the magnitude of thermal lensing in a high-energy diode-pumped Yb:YAG crystal. The spatio-temporal temperature profile of the gain medium and the focal length of the induced thermal lens are determined numerically. The influence of the repetition rate and pumping power on the temperature

We report high-energy, high-efficiency second harmonic generation in a near-infrared all-solid-state burst-mode picosecond laser at a repetition rate of 1 kHz with four pulses per burst using a type-I noncritical phase-matching lithium triborate crystal. The pulses in each burst have the same time delay ( ${\sim}1~\text{ns}$ ), the same pulse duration ( ${\sim}100~\text{ps}$ ) and different relative

Ultraintense laser-driven relativistic electrons provide a way of heating matter to high energy density states related to many applications. However, the transport of relativistic electrons in solid targets has not been understood well yet, especially in dielectric targets. We present the first detailed two-dimensional particle-in-cell simulations of relativistic electron transport in a silicon target

A tunable ultrafast intensity-rotating optical field is generated by overlapping a pair of 20 Hz, 800 nm chirped pulses with a Michelson interferometer (MI). Its rotating rate can be up to 10 trillion radians per second ( $\text{Trad}/\text{s}$ ), which can be flexibly tuned with a mirror in the MI. Besides, its fold rotational symmetry structure is also changeable by controlling the difference from

In this paper, we report the recent progress on the $1~\text{PW}/0.1~\text{Hz}$ laser beamline of Shanghai Superintense Ultrafast Laser Facility (SULF). The SULF-1 PW laser beamline is based on the double chirped pulse amplification (CPA) scheme, which can generate laser pulses of 50.8 J at 0.1 Hz after the final amplifier; the shot-to-shot energy fluctuation of the amplified pulse is as low as 1.2%

The second and final year of the Erasmus Plus programme ‘Innovative Education and Training in high power laser plasmas’, otherwise known as PowerLaPs, is described. The PowerLaPs programme employs an innovative paradigm in that it is a multi-centre programme, where teaching takes place in five separate institutes with a range of different aims and styles of delivery. The ‘in-class’ time is limited

To reduce the seed length while maintaining the advantages of the cuboid KDP-type crystal, a long-seed KDP crystal with size $471~\text{mm}\times 480~\text{mm}\times 400~\text{mm}$ is rapidly grown. With almost the same high cutting efficiency to obtain third harmonic generation oriented samples, this long-seed KDP-type crystal can be grown with a shorter seed than that of the cuboid KDP-type crystal

We study the optimization of collisionless shock acceleration of ions based on hydrodynamic modelling and simulations of collisional shock waves in gaseous targets. The models correspond to the specifications required for experiments with the $\text{CO}_{2}$ laser at the Accelerator Test Facility at Brookhaven National Laboratory and the Vulcan Petawatt system at Rutherford Appleton Laboratory. In

The development of laser performance models having real-time prediction capability for the OMEGA EP laser system has been essential in meeting requests from its user community for increasingly complex pulse shapes that span a wide range of energies. The laser operations model PSOPS provides rapid and accurate predictions of OMEGA EP laser-system performance in both forward and backward directions,

The second and final year of the Erasmus Plus programme ‘Innovative Education and Training in high power laser plasmas’, otherwise known as PowerLaPs, is described. The PowerLaPs programme employs an innovative paradigm in that it is a multi-centre programme, where teaching takes place in five separate institutes with a range of different aims and styles of delivery. The ‘in-class’ time is limited

A simple, compact, double-pass pumped Nd:YVO4 thin disk laser is demonstrated. Its continuous-wave performance with different Nd doping concentrations and thicknesses is investigated experimentally. The maximum output power of 17.7 W is achieved by employing a 0.5 at.% doped sample, corresponding to an optical-to-optical efficiency of 46% with respect to the absorbed pump power. In addition, a numerical

A developing application of laser-driven currents is the generation of magnetic fields of picosecond–nanosecond duration with magnitudes exceeding $B=10~\text{T}$ . Single-loop and helical coil targets can direct laser-driven discharge currents along wires to generate spatially uniform, quasi-static magnetic fields on the millimetre scale. Here, we present proton deflectometry across two axes of a

Muons produced by the Bethe–Heitler process from laser wakefield accelerated electrons interacting with high $Z$ materials have velocities close to the laser wakefield. It is possible to accelerate those muons with laser wakefield directly. Therefore for the first time we propose an all-optical ‘Generator and Booster’ scheme to accelerate the produced muons by another laser wakefield to supply a prompt

In this paper we review the design and development of a 100 J, 10 Hz nanosecond pulsed laser, codenamed DiPOLE100X, being built at the Central Laser Facility (CLF). This 1 kW average power diode-pumped solid-state laser (DPSSL) is based on a master oscillator power amplifier (MOPA) design, which includes two cryogenic gas cooled amplifier stages based on DiPOLE multi-slab ceramic Yb:YAG amplifier technology

Pulse contrast is a crucial parameter of high peak-power lasers since the prepulse noise may disturb laser–plasma interactions. Contrast measurement is thus a prerequisite to tackle the contrast challenge in high peak-power lasers. This paper presents the progress review of single-shot cross-correlator (SSCC) for real-time contrast characterization. We begin with the key technologies that enable an

Compared with end pumping fiber combiner, one of the advantages for side pumping combiner is the unlimited pumping points, which means multi-point or cascaded side pumping can be realized. However, the loss mechanism of the cascaded structure is rarely discussed. In this paper, we present the numerical and experimental investigation about the loss mechanism of a two-stage-cascaded side pumping combiner

An all-fiberized and narrow-bandwidth master oscillator power amplification (MOPA) system with record output power of 4 kW level and slope efficiency of 78% is demonstrated. Tandem pumping strategy is tentatively introduced into the narrow-bandwidth MOPA system for thermally induced mode instability (TMI) suppression. The stimulated Brillouin scattering (SBS) effect is balanced by simply using one-stage

Polarization mode dispersion (PMD) in fibers for high-power lasers can induce significant frequency modulation to amplitude modulation (FM-to-AM) conversion. However, existing techniques are not sufficiently flexible to achieve efficient compensation for such FM-to-AM conversion. By analyzing the nonuniform transmission spectrum caused by PMD, we found that the large-scale envelope of the transmission

High power superfluorescent fiber sources (SFSs), which could find wide applications in many fields such as middle infrared laser generation, Raman fiber laser pumping and spectral beam combination, have experienced a flourishing time in recent years for its unique properties, such as short coherence length and high temporal stability. The challenge for performance scalability of powerful SFS mainly

The Orion facility at the Atomic Weapons Establishment in the United Kingdom has the capability to operate one of its two 500 J, 500 fs short-pulse petawatt beams at the second harmonic, the principal reason being to increase the temporal contrast of the pulse on target. This is achieved post-compression, using 3 mm thick type-1 potassium dihydrogen phosphate crystals. Since the beam diameter of the

An all-fiberized high-average-power narrow linewidth ns pulsed laser with linear polarization is demonstrated. The laser system utilizes a typical master oscillator power amplifier (MOPA) configuration. The stimulated Brillouin scattering (SBS) is effectively suppressed due to the short fiber length and large mode area in the main amplifier, combined with the narrow pulse duration smaller than the

Ytterbium-doped fibers have become the optimum gain media of high-power fiber lasers thanks to a simple energy structure, which strongly reduces the excited state absorption, and a low quantum defect and a high optic–optic conversion efficiency, which means the low thermal load. In this paper, we take a review of the current state of the art in terms of $\text{Yb}^{3+}$ doped fibers for high-power

The nonlinear absorption (NLA) properties of potassium dideuterium phosphate crystals at 515 nm under different excitation laser intensities are investigated with the Z-scan technique. Two critical intensities are highlighted: the critical intensity for exciting the NLA and the critical intensity of the multiphoton absorption mechanism transition. Experimental results indicate the existence of defect

A novel laboratory experimental design is described that will investigate the processing of dust grains in astrophysical shocks. Dust is a ubiquitous ingredient in the interstellar medium (ISM) of galaxies; however, its evolutionary cycle is still poorly understood. Especially shrouded in mystery is the efficiency of grain destruction by astrophysical shocks generated by expanding supernova remnants

As a promising new way to generate a controllable strong magnetic field, laser-driven magnetic coils have attracted interest in many research fields. In 2013, a kilotesla level magnetic field was achieved at the Gekko XII laser facility with a capacitor–coil target. A similar approach has been adopted in a number of laboratories, with a variety of targets of different shapes. The peak strength of the

We present a parameter estimate for continua, and He-like triplets of the high resolution X-ray spectra with a Bayesian inference and a Markov Chain Monte Carlo (MCMC) tool. The method is applied for Vela X-1 with three different orbital phases ( $\unicode[STIX]{x1D719}$ ), Eclipse, $\unicode[STIX]{x1D719}=0.25$ , and $\unicode[STIX]{x1D719}=0.5$ , which are adopted from the Chandra High-Energy Transmission

In this work we have conducted a study on the radiative and spectroscopic properties of the radiative precursor and the post-shock region from experiments with radiative shocks in xenon performed at the Orion laser facility. The study is based on post-processing of radiation-hydrodynamics simulations of the experiment. In particular, we have analyzed the thermodynamic regime of the plasma, the charge

A new target design is presented to model high-energy radiative accretion shocks in polars. In this paper, we present the experimental results obtained on the GEKKO XII laser facility for the POLAR project. The experimental results are compared with 2D FCI2 simulations to characterize the dynamics and the structure of plasma flow before and after the collision. The good agreement between simulations

A study of the structure of the electric and magnetic fields of ultraintense laser pulses focused by an off-axis parabolic mirror is reported. At first, a theoretical model is laid out, whose final equations integration allows the space and time structure of the fields to be retrieved. The model is then employed to investigate the field patterns at different times within the optical cycle, for off-axis

We report here a high-power, wavelength tunable and narrow linewidth $1.5~\unicode[STIX]{x03BC}\text{m}$ all-fiber laser amplifier based on a tunable diode laser and Er-Yb co-doped fibers. The laser wavelength can be precisely tuned from 1535 nm to 1580 nm, which covers many absorption lines of mid-infrared laser gases, such as $\text{C}_{2}\text{H}_{2}$ , HCN, CO, and HI. The maximum laser power is

In this paper, we present a model characterizing the interaction of a radiative shock (RS) with a solid material, as described in a recent paper (Koenig et al., Phys. Plasmas, 24, 082707 (2017)), the new model is then related to recent experiments performed on the GEKKO XII laser facility. The RS generated in a xenon gas cell propagates towards a solid obstacle that is ablated by radiation coming from

We demonstrate a nonlinearity optimization method by altering distribution of passive fibers in a dissipative-soliton mode-locked fiber laser to level up output parameters. In the numerical simulation, we found that the passive fiber segment after gain fiber characterizes the highest average B-integral among fiber segments. By reducing the length of this fiber section and keeping the total passive

In this paper, we experimentally investigated the extreme frequency shift in high-power Raman fiber laser (RFL). The RFL was developed by using a pair of fiber Bragg gratings with fixed and matched central wavelength (1120 nm) combined with a piece of 31-m-long polarization maintaining (PM) passive fiber adopted as Raman gain medium. The pump source was a homemade high-power, linearly polarized (LP)

We present a recent progress of the SG-II 5PW facility, which designed a multi-petawatt ultrashort pulse laser based on optical parametric chirped-pulse amplification (OPCPA). The prior two optical parametric amplifiers have been accomplished and chirped pulses with an energy of 49.7 J and a full-width-at-half-maximum (FWHM) spectrum bandwidth of 85 nm have been achieved. In the PW-scale optical parametric

Boron nitride (BN) nanosheets incorporated silica antireflective (AR) coating was successfully prepared on fused silica substrate to improve the antilaser-damage ability of transmissive optics used in high-power laser systems. The BN nanosheets were obtained by urea assisted solid exfoliation, and then incorporated into basic-catalyzed silica sols without any further treatment. The transmission electron

We propose a novel model to explain the physical process of the thermally induced core laser leakage (TICLL) effect in a high power co-pumped ytterbium doped fiber (YDF) amplifier. This model considers the thermally induced mode bending loss decrease and the thermally induced mode instability (TMI) in the coiled YDF, and is further used to reproduce the TICLL effect in the high power co-pumped step-index

The power scaling on mid-infrared Raman fibre lasers (RFLs) is in demand for applications in health, environment and security. In this paper, we present the simulated laser behaviours of the tellurite glass RFLs pumped by 300-W Tm-doped fibre lasers (TDFLs) at $2~\unicode[STIX]{x03BC}\text{m}$ for the first time. By combining the advantages of the TDFLs and tellurite fibre, the output power at $2.

Supersonic flows with high Mach number are ubiquitous in astrophysics. High-powered lasers also have the ability to drive high Mach number, radiating shock waves in laboratory plasmas, and recent experiments along these lines have made it possible to recreate analogs of high Mach-number astrophysical flows under controlled conditions. Streak cameras such as the Rochester optical streak system (ROSS)

An optically addressed liquid crystal modulator for wavefront control of 1053 nm laser beam is reported in this paper. Its working principle, control method and spatial phase modulation capability are mainly introduced. A new method of measuring the relationship between gray level and phase retardation is proposed. The rationality of the curve is further confirmed by designing special experiments.

We present a new experimental platform for studying laboratory astrophysics that combines a high-intensity, high-repetition-rate laser with the Large Plasma Device at the University of California, Los Angeles. To demonstrate the utility of this platform, we show the first results of volumetric, highly repeatable magnetic field and electrostatic potential measurements, along with derived quantities

We demonstrate an all polarization-maintaining (PM) fiber mode-locked laser seeded, hybrid fiber/solid-slab picosecond pulse laser system which outputs $40~\unicode[STIX]{x03BC}\text{J}$ , 10 ps pulses at the central wavelength of 1064 nm. The beam quality factors $M^{2}$ in the unstable and stable directions are 1.35 and 1.31, respectively. $15~\unicode[STIX]{x03BC}\text{J}$ picosecond pulses at the

Compared with traditional uniform fibers, tapered fiber has numerous unique advantages, such as larger mode area, higher pump absorption, suppression to nonlinear effects, and maintaining good beam quality. In this manuscript, we have constructed an all-fiberized fiber amplifier which is based on a piece of ytterbium-doped tapered double-clad fiber (T-DCF). The fiber amplifier is operated under continuous

In high power laser facility for inertial confinement fusion research, final optics assembly (FOA) plays a critical role in the frequency conversion, beam focusing, color separation, beam sampling and debris shielding. The design and performance of FOA in SG-II Upgrade laser facility are mainly introduced here. Due to the limited space and short focal length, a coaxial aspheric wedged focus lens is

We present possible conceptual designs of a laser system for driving table-top free-electron lasers based on terahertz acceleration. After discussing the achievable performances of laser amplifiers with Yb:YAG at cryogenic and room temperature and Yb:YLF at cryogenic temperature, we present amplification modules with available results and concepts of amplifier chains based on these laser media. Their

Enhanced acceleration of protons to high energy by relatively modest high power ultra-short laser pulses, interacting with snow micro-structured targets was recently proposed. A notably increased proton energy was attributed to a combination of several mechanisms such as localized enhancement of the laser field intensity near the tip of $1~\unicode[STIX]{x03BC}\text{m}$ size whisker and increase in

Temporal contrast is one of the crucial physical determinants which guarantee the successful performance of laser–matter interaction experiments. We generally reviewed the influences on the temporal contrast in three categories of noises based on the requirement by the physical mechanisms. The spatiotemporal influences on temporal contrast at the focal region of the chromatic aberration and propagation

Auto-alignment is a basic technique for high-power laser systems. Special techniques have been developed for laser systems because of their differing structures. This paper describes a new sensor for auto-alignment in a laser system, which can also serve as a reference in certain applications. The authors prove that all of the beam transfer information (position and pointing) can theoretically be monitored

Light carrying orbital angular momentum (OAM) has a spatial distribution of intensity and phase, which attracts considerable interest regarding several potential applications in optical and quantum scenarios recently. Spiral phase plates are commonly used elements for generating and analyzing OAM states. In this study, we put forward a method of directly writing binary multi-sector phase plates using

A new crystal spectrometer for application in X-ray opacity experiments is proposed. The conditions necessary to yield broad spectral coverage with a resolution ${>}$ 500, strong rejection of hard X-ray backgrounds and negligible source broadening for extended sources are formulated. In addition, the design, response modeling and reporting of an elliptical crystal spectrometer in conjunction with a

Faraday effect measurements of holmium oxide (Ho2O3) ceramics-based magneto-optical materials, highly potential material candidates for high-energy laser Faraday isolators, are presented in this paper. Temperature dependence of the Verdet constant of nondoped Ho2O3 ceramics was measured for temperatures 15–305 K at $1.064~\unicode[STIX]{x03BC}\text{m}$ wavelength. The Verdet constant dispersion for