Femtosecond mid-IR optical vortex laser based on optical parametric chirped pulse amplification

Abstract

A femtosecond mid-infrared optical vortex laser can be used for high harmonic generation to extend cutoff energy to the kilo-electron-volt range with orbital angular momentum, as well as other secondary radiations. For these, we demonstrate a high-energy femtosecond 4 μm optical vortex laser based on optical parametric chirped pulse amplification (OPCPA) for the first time. The optical vortex seed is generated from a femtosecond 4 μm laser by a silicon spiral phase plate with the topological charge l of 1 before the stretcher. Through using a two-stage collinear OPCPA amplifier, the chirped vortex pulse is amplified to 12.4 mJ with 200 nm full width at half-maximum bandwidth. After compression, the vortex laser pulse with 9.53 mJ, 119 fs can be obtained. Furthermore, the vortex characteristics of the laser beam are investigated and evaluated. This demonstration can scale to generate a higher-peak-power vortex mid-IR laser and pave a new way for high field physics.

Table-top optical parametric chirped pulse amplifiers: past and present

“…A possibility of OPCPA to amplify complex-shaped wave packets was studied numerically, demonstrating that broadband X-pulses with specific spatial and temporal chirps can be efficiently amplified without phase distortions and self-compressed during free-space propagation onto the target area 195 . Very recently, amplification of chirped vortex pulse at 4 μm to multi-mJ energy and its compression to less than 9 optical cycles was experimentally demonstrated in OPCPA system based on KTA crystal 196 .…”

Second harmonic generation of laser beams in transverse mode locking states

“…The nonlinear frequency conversion process of the structured ultrafast laser beam was investigated gradually. [15][16][17][18] In addition to the structured ultrafast lasers, investigations of the nonlinear frequency conversion property of Laguerre-Gaussian (LG) beams or vortex laser beams have emerged in the last ten years. Four-wave mixing 19,20 and sum frequency, 21 or other frequency upconversion methods, 22 were studied by external cavity orbital angular momentum (OAM) modulations and nonlinear interactions.…”

Directly Determining Orbital Angular Momentum of Ultrashort Laguerre–Gauss Pulses via Spatially‐Resolved Autocorrelation Measurement

“…Ultrashort pulses carrying orbital angular momentum (OAM) have gained an increasing interest in the community of ultrafast photonics and structured light. [1][2][3][4][5][6][7][8][9] An important reason for this is that optical vortices with ultrahigh peak power and ultrashort duration provide a new tool to explore novel applications, as well as fundamental aspects of physics. For instance, ultrashort vortex pulses structured in their spatial or polarization degrees of freedom, can produce light fields with extraordinary spatiotemporal and topological structures.…”