Generating long sequences of high-intensity femtosecond pulses

We present an approach to create pulse sequences extending beyond 150~picoseconds in duration, comprised of $100~\mu$J femtosecond pulses. A quarter of the pulse train is produced by a high-resolution pulse shaper, which allows full controllability over the timing of each pulse. Two nested Michelson interferometers follow to quadruple the pulse number and the sequence duration. To boost the pulse energy, the long train is sent through a multi-pass Ti:Sapphire amplifier, followed by an external compressor. A periodic sequence of 84~pulses of 120~fs width and an average pulse energy of 107~$\mu$J, separated by 2~ps, is demonstrated as a proof of principle.