Laser-wakefield acceleration offers the promise of a compact electron accelerator for generating a multi-GeV electron beam using the huge field gradient induced by an intense laser pulse, compared to conventional rf accelerators. However, the energy and quality of the electron beam from the laser-wakefield accelerator have been limited by the power of the driving laser pulses and interaction properties in the target medium. Recent progress in laser technology has resulted in the realization of a petawatt (PW) femtosecond laser, which offers new capabilities for research on laser-wakefield acceleration. Here, we present a significant increase in laser-driven electron energy to the multi-GeV level by utilizing a 30-fs, 1-PW laser system. In particular, a dual-stage laser-wakefield acceleration scheme (injector and accelerator scheme) was applied to boost electron energies to over 3 GeV with a single PW laser pulse. Three-dimensional particle-in-cell simulations corroborate the multi-GeV electron generation from the dual-stage laser-wakefield accelerator driven by PW laser pulses.

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High-intensity lasers are critical for the exploration of strong field quantum electrodynamics. We report here a demonstration of laser intensity exceeding 1 0 23 W / c m 2 with the CoReLS petawatt (PW) laser. After wavefront correction and tight focusing with a two-stage adaptive optical system and an f/1.1 ( f = 300 m m ) off-axis parabolic mirror, we obtained near diffraction-limited focusing with a spot size of 1.1 µm (FWHM). From the measurement of 80 consecutive laser shots at 0.1 Hz, we achieved a peak intensity of ( 1.1 ± 0.2 ) × 1 0 23 W / c m 2 , verifying the applicability of the ultrahigh intensity PW laser for ultrahigh intensity laser–matter interactions. From the statistical analysis of the PW laser shots, we identified that the intensity fluctuation originated from air turbulence in the laser beam path and beam pointing. Our achievement could accelerate the study of strong field quantum electrodynamics by enabling exploration of nonlinear Compton scattering and Breit–Wheeler pair production.

We demonstrated the generation of 4.2 PW laser pulses at 0.1 Hz from a chirped-pulse amplification Ti:sapphire laser. The cross-polarized wave generation and the optical parametric chirped-pulse amplification stages were installed for the prevention of the gain narrowing and for the compensation of the spectral narrowing in the amplifiers, obtaining the spectral width of amplified laser pulses of 84 nm (FWHM), and enhancing the temporal contrast. The amplified laser pulses of 112 J after the final booster amplifier were compressed to the pulses with 83 J at 19.4 fs with a shot-to-shot energy stability of 1.5% (RMS). This 4.2 PW laser will be a workhorse for exploring high field science.

High-contrast, 30 fs, 1.5 PW laser pulses are generated from a chirped-pulse amplification (CPA) Ti:sapphire laser system at 0.1 Hz repetition rate. The maximum output energy of 60.2 J is obtained, at a pump energy of 120 J, from a booster amplifier that is pumped by four frenquency-doubled Nd:glass laser systems. During amplification, parasitic lasing is suppressed by index matching fluid with absorption dye and the careful manipulation of the time delay between the seed and pump pulses. An amplified pulse passes through a pulse compressor consisting of four gold-coated gratings. After compression, the measured pulse duration is 30 fs, and the output energy is 44.5 J, yielding a peak power of about 1.5 PW. The output energy of 44.5 J and output power of 1.5-PW are the highest values ever achieved from the femtosecond CPA Ti:sapphire laser system. To maintain a sufficiently high temporal contrast, a saturable absorber is installed in the front-end system with two ultrafast Pockels cells in order to minimize the amplified spontaneous emission (ASE) and pre-pulse intensity. An adaptive optics system is implemented for PW laser pulses and a focused intensity of about 1 × 10(22) W/cm(2) can be obtained when an f/3 optic is used.