Creation of femtosecond sheet-like bunches for driving optical-scale dielectric slab accelerator structures

Abstract

Optically chopped bunches can be created by placing a beam stop with an off-axis hole following laser-driven cyclotron autoresonance acceleration. For example, a 500 MeV electron beam driven by a 5 TW/10.6 micron laser can be chopped into bunches with diameter ~50 microns and length ~1 micron. It is furthermore shown that the bunches can be elongated in one transverse dimension and compressed in the other using a quadrupole magnet, so as to serve as the driver for an optical-scale dielectric wake field accelerator. Bunch length spreading from space charge is examined to find limits to transport of pC, micron long bunches.