Abstract
High-energy light transients hold promise for extending the photon energy of isolated attosecond pulses to multi-keV regime with a higher photon flux compared to other conventional drivers [1]. It has been suggested that the energy of light transients can be scaled by employing several parallel optical parametric amplifier (OPA) at different carrier frequencies prior to the temporal field synthesis [2,3]. Such a concept requires a high-energy laser frontend, and carrier-envelope phase (CEP) stable, multi-octave pulses to seed and pump several OPA chains at different carrier frequencies. Relative temporal synchronization between: i) the pump and the seed pulses, and ii) different OPA channels, is of crucial importance, as it defines the ultimate stability of the synthesized light transients. Direct generation of the multi-octave seed spectrum from the pump laser, assures the stability of the amplified spectrum at each OPA channel, in addition to the temporal synchronization between the parallel OPA channels. In what follows we discuss an all ytterbium frontend for high energy field synthesis and demonstrate how the temporal jitter in this scheme is only restricted to long term drift.