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In this study, we numerically simulate the evolution of the orbital angular momentum (OAM) spectrum of a vortex laser beam in the optical parametric chirped pulse amplification (OPCPA) process, which is an effective technical method to realize ultra-intense and ultra-short vortex laser amplification. The results show that the proportion of the vortex laser beam with 100% topological charge (TC) of 1 decreases to 97.44% with the enhancement of the saturation amplification after amplification by a 15 mm length LBO pumped by a 526.5 nm laser with a pump intensity of 1.74 GW/cm

A new type of beam called the NPEP-BG (a Bessel–Gaussian (BG) beam with a spiral phase term of a new power-exponent-phase (NPEP)) is theoretically studied in this paper. The results show that the number of singularities of the phase and side lobes of the intensity of this beam were equal to the topological charges (TCs) and the beam has the characteristics of self-healing during propagation. The NPEP-BG beam combined the partial characteristics of the new power-exponent-phase vortex (NPEPV) and the Bessel–Gaussian beam. At the focus of the beam, the characteristic like a perfect vortex beam was present, in which the focal radius is stable and independent of the topological charge. There are multi-focal spots around a ring in the focal plane, meaning that the NPEP-BG beam has a potential for application in multi-particle manipulation.

In this letter, we report the demonstration of terawatt (TW)-scale femtosecond vortex laser pulses based on noncollinear optical parametric chirped-pulse amplification (OPCPA) centered at 800 nm. To the best of our knowledge, this is the first experimental study of amplification for OPCPA-based vortex pulses to achieve a powerful ultrafast (TW-scale) vortex pulse output. In this experiment, a 0.5-mJ broadband chirped vortex pulse was amplified to 47 mJ with a 15-mm-long LiB3O5 crystal. The double-pass grating pair compressor with an efficiency of 65% maintained the beam vortex, and a pulse of width 30.1 fs was obtained, corresponding to a peak power of 1.02 TW. This laser can be used in studies on nonlinear optics and relativistic laser-plasma interactions, compact plasma-based accelerators, and light sources.