Amplification of Laguerre-Gaussian laser pulses in plasma by copropagating Gaussian pulses.

Laguerre-Gaussian (LG) laser beams have many interesting applications due to their unique field structure. However, the generation of intense LG beams remains challenging because of the limited damage threshold of intensity for optical elements used for the conversion from normal Gaussian beams to LG beams. Here, we propose a plasma-based scheme to amplify a LG pulse through energy transfer from copropagating multiple Gaussian pulses as pumps. It is found that efficient energy transfer can be realized by properly choosing the relative phase difference between the LG pulse and the Gaussian pulses, where the intensity of the LG pulse can be enhanced by nearly two orders of magnitude. This scheme works for either weakly or highly relativistic intense lasers, as well as for LG pulses with different topological charges. Furthermore, the properties of the amplified LG pulse can be manipulated by controlling the Gaussian pulses, such as the pump laser beam number, laser intensity, and propagation direction. Our studies provide a way of using plasma optics to amplify LG lasers to relativistic high intensity and manipulate their spatial structure for applications.