Shaping ellipsoidal laser pulses in the scheme with black analog masks for photoinjector applications

Abstract

Today the electron beam emittance minimization race seems to slack due to insufficiency of beam shaping techniques. To fill the gap we propose a method for shaping a sharp 3D ellipsoidal boundary of laser pulses used in a photoinjector. To avoid distortions in the profiled laser beam, only black analog masks are exploited as shaping elements. A highly promising experimental distribution with a 3D boundary thickness better than 10% was obtained at the fundamental harmonic. The proposed scheme can be easily modified for multiplied harmonics of radiation.

Towards Implementation of 3D Amplitude Shaping at 515 nm and First Pulseshaping Experiments at PITZ

“…A version of the proposed scheme to generate ellipsoidal pulses has been installed at PITZ and was upgraded over the past few years [25]. Other promising approaches are the application of profiled Chirped Volume Bragg gratings [26], the implementation of an absorption mask for amplitude shaping [27], or the usage of oppositely chirped pulses for frequency conversion [28]. However, when pulseshaping is realized in the IR, a two-step frequency conversion to green and then UV is required, which is susceptible to instabilities when trying to achieve high conversion efficiencies.…”