The petawatt (PW) laser has experienced a rapid development in the past two decades, and tens of giant facilities have been constructed worldwide. After realizing 10–100 PW, it seems to be close to some sort of engineering limit but its focused peak intensity still is much lower than the Schwinger limit, and therefore some technology improvements or innovations become indispensable for further increasing the peak power as well as the focused peak intensity. By quick reviewing the development of the PW laser in history, it is shown that reducing the pulse duration to near a single optical cycle is a feasible (easy and cheap) choice for this purpose. Here, technologies for the optical‐cycle pulse generation, ultrabroadband amplification, and capability boosting that aim to provide possible approaches for optical‐cycle PW lasers are briefly reviewed and discussed. Meanwhile, key bottlenecks that challenge the current as well as the future short‐pulse PW lasers and their possible solutions are summarized and discussed. This technology review aims to provide a possible roadmap for the next‐stage development of the short‐pulse PW laser.

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/lpor.202100705

Further Development of the Short‐Pulse Petawatt Laser: Trends, Technologies, and Bottlenecks

The petawatt (PW) laser facility of the Berkeley Lab Laser Accelerator (BELLA) Center has recently commissioned its second laser pulse transport line. This new beamline can be operated in parallel with the first beamline and enables strong-field quantum electrodynamics (SF-QED) experiments at BELLA. In this paper, we present an overview of the upgraded BELLA PW facility with a SF-QED experimental layout in which intense laser pulses collide with GeV-class laser-wakefield-accelerated electron beams. We present simulation results showing that experiments will allow the study of laser-particle interactions from the classical to the SF-QED regime with a nonlinear quantum parameter of up to $$\chi \sim $$ 2. In addition, we show that experiments will enable the study and production of GeV-class, mrad-divergence positron beams via the Breit–Wheeler process. 

/pdf/strong-field-qed-experiments-using-the-bella-pw-laser-dual-3b5wdiqj.pdf

Strong-field QED experiments using the BELLA PW laser dual beamlines

Manganese dioxide (MnO 2 ) is a widely used and well-studied 3-dimensional (3D) transition metal oxide, which has advantages in ultrafast optics due to large specific surface area, narrow bandgap, multiple pores, superior electron transfer capability, and a wide range of light absorption. However, few studies have considered its excellent performance in ultrafast photonics. γ-MnO 2 photonics devices were fabricated based on a special dual-core, pair-hole fiber (DCPHF) carrier and applied in ultrafast optics fields for the first time. The results show that the soliton molecule with tunable temporal separation (1.84 to 2.7 ps) and 600-MHz harmonic solitons are achieved in the experiment. The result proves that this kind of photonics device has good applications in ultrafast lasers, high-performance sensors, fiber optical communications, etc., which can help expand the prospect of combining 3D materials with novel fiber for ultrafast optics device technology. 

https://spj.science.org/doi/pdf/10.34133/ultrafastscience.0006?download=true

High-performance γ-MnO
 2
 dual-Core pair-hole fiber for ultrafast photonics

Recent progress on mid-infrared pulsed fiber lasers and the applications

New laser facilities will reach intensities of $10^{23} \textrm{W cm}^{-2}$. This advance enables novel experimental setups in the study of laser-plasma interaction. In these setups with extreme fields quantum electrodynamic (QED) effects like photon emission via non-linear Compton scattering and Breit-Wheeler pair production become important. We study high-intensity lasers grazing the surface of a solid-state target by two-dimensional particle-in-cell simulations with QED effects included. The two laser beams collide at the target surface at a grazing angle. Due to the fields near the target surface electrons are extracted and accelerated. Finally, the extracted electrons collide with the counter-propagating laser, which triggers many QED effects and leads to a QED cascade under a sufficient laser intensity. Here, the processes are studied for various laser intensities and angles of incidence and finally compared to a seeded vacuum cascade. Our results show that the proposed target can yield many order of magnitude more secondary particles and develop a QED cascade at lower laser intensities than the seeded vacuum alone. 

/pdf/qed-effects-at-grazing-incidence-on-solid-state-targets-wagva9jo.pdf

QED effects at grazing incidence on solid-state targets

Here, we report the recent progress on the front end developed for the 100 PW-class laser facility. Using 3 stages of optical parametric chirped-pulse amplification (OPCPA) based on lithium triborate (LBO) crystals, we realized a 5.26 J/0.1 Hz amplified output with a bandwidth over 200 nm near the center wavelength of 925 nm. After the compressor, we obtained a pulse duration of 13.4 fs. As the compression efficiency reached 67%, this OPCPA front end could potentially support a peak power of 263 TW at a repetition rate of 0.1 Hz. To the best of our knowledge, among all the 100 TW-level OPCPA systems, it shows the widest spectral width, the shortest pulse duration, and it is also the first OPCPA system working at a repetition-rate mode.

13.4 fs, 0.1 Hz OPCPA Front End for the 100 PW-Class Laser Facility

In this paper, we report that the angular dispersion of the output pulses in a nonlinear process can be efficiently compensated by using a cascaded prism(s) and short hollow-core fiber (HCF) configuration. Here, the prism(s) is used to suppress the angular dispersion and transform it into spatial chirp, while the HCF is used for removing this spatial chirp and the residual angular dispersion, which can also significantly improve the beam quality. The feasibility of this novel method is numerically and experimentally investigated with the ultra-broadband idler pulses centered at 1250 nm wavelength and generated by an LBO crystal based non-collinear optical parametric amplifier. The proof-of-principle experiment shows that the angular dispersion can be effectively removed and ultra-broadband idler pulses with good spectral quality and spatial profile can be obtained. The total transmission efficiency in the experiment is around 67% and the measured M x2 and M y2 can reach 1.12 and 1.04, respectively. To the best of our knowledge, this is the first reported ultra-broadband angular dispersion compensation scheme combining prism(s) and HCF, which can remarkably eliminate the angular dispersion while simultaneously possesses high efficiency, good spectral and beam spatial quality.

Haidong Chen

Papers

13.4 fs, 0.1 Hz OPCPA Front End for the 100 PW-Class Laser Facility

Angular dispersion compensation for ultra-broadband pulses by using a cascaded prism and hollow-core fiber configuration.

Investigation of compression grating misalignment in ultra-high peak power femtosecond laser systems

High-efficiency, ultra-broadband ns-OPCPA with high temporal contrast based on dual-crystal scheme