High-gain amplification for femtosecond optical vortex with mode-control regenerative cavity

Abstract

Ultra-intense femtosecond vortex pulses can provide an opportunity to investigate the new phenomena with orbital angular momentum (OAM) involved in extreme cases. This paper reports a high gain optical vortex amplifier for intense femtosecond vortex pulses generation. Traditional regeneration amplifiers can offer high gain for Gaussian mode pulses but cannot amplify optical vortex pulses while maintaining the phase singularity because of mode competition. Here, we present a regeneration amplifier with a ringshaped pump. By controlling the radius of the pump, the system can realize the motivation of LG0,1(-1) mode and the suppression of Gaussian mode. Without seeds, the amplifier has a donut-shaped output containing two opposite OAM states simultaneously, as our prediction by simulation. If seeded a pulse of a topologic charge of 1 or-1, the system will output an amplified LG0,1(-1) mode pulse with the same topologic charge as the seed. To our knowledge, this amplifier can offer the highest gain as 1.45×10 6 for optical vortex amplification. Finally, we obtain a 1.8 mJ, 51 fs compressed optical vortex seeded from a 2 nJ optical vortex.

Twisted Light in a Single‐Crystal Fiber: Toward Undistorted Femtosecond Vortex Amplification

“…[ 31 ] However, spectral, temporal, and spatial phase distortions caused by nonlinear effects are inevitable for such femtosecond pulses when approaching a high‐energy level. [ 32 ] The alternative multipass [ 33 ] or regenerative [ 34 ] bulk laser amplifiers that can deliver high‐peak power pulses through CPA, provide only low average power and gain due to the intrinsic mode mismatch between pump and vortex beams which requires an additional tailoring of the pump light as a trade‐off. [ 34 ] In addition, undesirable spatial and topological‐charge dispersion in the pulse stretching and/or compression processes, and the thermally induced beam distortion still require a thorough assessment.…”

“…So far, several approaches have been adopted to amplify broadband femtosecond vortex beams, which, from technological viewpoint, can be classified into two categories: nonlinear optical processes [ 26–28 ] and direct laser amplification. [ 29–34 ] The former mainly refers to optical parametric amplification (OPA) and in particular chirped pulse OPA (CPOPA). Apart from the additional limitation for the maximum efficiency due to the amplification of two waves, this approach requires a severe trade‐off between pump–seed mode‐matching and efficiency when it comes to power scaling of vortex beams which restricts the achievable average output powers.…”

Forty-five terawatt vortex ultrashort laser pulses from a chirped-pulse amplification system

“…However, further promotion of the output peak power may be limited by the sizes of the nonlinear optical crystals. Recently, our group has experimentally realized high-quality 1.8-mJ, 51-fs pulses from a mode-controlled regenerative amplification cavity [ 25 ] based on chirped-pulse amplification (CPA) [ 26 ] seeded with its 2-nJ seeds. However, in the cavity, the pump and the signal should be matched accurately, and the output TC cannot be flexibly changed unless by a structural modification of the cavity.…”

Optical Wavefront Detection: A Beginner Tutorial

“…Therefore, measuring the aberrated wavefront is quite important. Moreover, the high-order modes of lasers have special wavefront structures, such as Laguerre-Gaussian beams and Hermitian-Gaussian beams [12][13][14]. Diagnosing the wavefront of this kind of structured light can help us to better understand and further study these types of laser beams.…”