A Stable 200TW / 1Hz Ti:sapphire laser for driving full coherent XFEL

• A stable 200TW/1Hz Ti:sapphire laser is designed for driving full coherent XFEL.
• The measured energy stability of the amplified pulse is about 0.54% in rms value.
• The laser pulse is split into two beams for LWFA and HHG respectively.
• The benefit of the scheme is to improve the timing jitter between the two beams.

Basic features of the ultra-short Ti:sapphire laser for driving compact X-ray free electron laser (XFEL) seeded by laser-driven high harmonic generation (HHG) at SIOM (Shanghai, China) is presented. The laser system consists of four-stage Ti:sapphire amplifiers and can produce 8 J energy at 1 Hz repetition rate after the final power amplifier. The best shot-to-shot energy fluctuation is as low as 0.54% in rms value, which is a desirable characteristic for driving stable electron acceleration and HHG seed. After compression, maximal pulse energy of 5.6 J and pulse duration of 27 fs can be obtained, the corresponding pulse peak power is above 200 TW. To achieve full coherent XFEL, the amplified chirped laser beam is split into two beams after the final power amplifier. After compression in two independent compressors, the two laser beams can be used to drive laser wakefield acceleration (LWFA) and HHG respectively. The benefit of such a scheme is to improve the timing jitter and achieve all-optical synchronization between the electron beam and HHG seed in the near future.