Development of Table-Top Free Electron Lasers Based on a Laser Wakefield Accelerator

In this chapter, we introduce the recent advances on high-quality laser wakefield accelerator and table-top free electron lasing experiments. By conducting a simple supersonic gas nozzle inserted with a perforated baffle, high quality electron beams with peak energy centered at 490 MeV, energy spreads of around 0.5%, average charge of around 30 pC and r.m.s. divergence of approximately 0.2 mrad, can be experimentally obtained. Under the optimized conditions, we demonstrate the table-top free electron lasing in the exponential-gain regime. The amplified undulator radiation has a central wavelength of 27 nm and a maximum photon number of around 1010 per shot, yielding a maximum radiation energy of approximate 150 nJ. The maximum gain of the radiation reaches 100-fold in the third of the three undulators, confirming the successful operation in the exponential gain regime. This is the first time for the table-top free electron lasing driven by laser wakefield accelerators and pave the way for future table-top X-ray free electron lasers with broad applications.