Generation of phase-stable sub-mJ ultrashort laser pulse bursts with extremely high scalable pulse number

We demonstrate generation of bursts that consist of up to 40 ultrashort pulses with 10 μJ pulse energy, 250 fs pulse duration and an ultrashort tunable spacing, from picoseconds to nanoseconds, corresponding to a terahertz intraburst repetition rate. This was achieved by the build-up of a novel thermally-stable sub-mJ Vernier Regenerative Amplifier (RA), whose round-trip detuning is similar to its master oscillator round-trip time. The RA includes two cavities pumped from a common diode, and is able to provide for either 2 bursts (one burst out of each cavity), or for one burst and a synchronous reference pulse for characterization.