Feedback-stabilized Nd:YLF amplifier system for generation ofpicosecond pulse trains of an exactly rectangular envelope

摘要

We describe the amplifier chain of the photocathode laser of thenTESLA Test Facility. This chain is optimized for amplification of trainsnof picosecond pulses. At its output, pulse trains with a rectangularlynshaped envelope of 0.7% flatness and a long-term stability of the energynin the individual picosecond pulses in excess of 0.9% are obtained. Thisnstability is achieved by using a computerized feedback control system,nwhich we describe in detail together with the versatile feedbacknalgorithm applied. The feedback loop performs a tight adjustment of bothnthe shape and magnitude of the flashlamp pulses as well as the startingntime of the pump with respect to the pulse train. High-current insulatedngate bipolar transistors are used to directly manipulate the flashlampncurrent in a microsecond time scale