Longitudinal Laser Pulse Shaping for Low-Emittance Electron-Beam Generation

Several X-ray free electron laser (FEL) projects require a very low-emittance electron beam and laser pulse shaping is needed for low-emittance electron-beam generation. Especially, a uniform laser pulse shape is very efficient. We have designed a 4-pulse generator for longitudinally uniform laser pulse shaping and a cross-correlation system to diagnose the shaped pulse. In this article, we introduce a 4-pulse generator for longitudinal laser pulse shaping and a technique to make a longitudinally uniform shape. In addition, we introduce a specially designed cross-correlation system for mixed polarizations, with which we can diagnose the laser pulse.11sciescopuskc