Coherent beam combining in the femtosecond regime

This chapter discusses the principles and specifics of coherent beam combining in the femtosecond regime with the aim of scaling the power of laser systems. It also describes some experiments that have been performed so far in this field. These experimental results have been mostly obtained in the context of fiber-based amplifier systems, with pulse energies ranging from a few microjoules to a few millijoules. The chapter talks about the coherent addition of ultrashort optical pulses in different configurations. It explains the idea of divided-pulse amplification that makes use of temporal multiplexing to scale down the peak power prior to amplification and temporal coherent recombining. The chapter presents the cavity enhancement experiments in the femtosecond regime. It finally evaluates the pulse synthesis experiments, where pulses with different spectral contents are coherently combined to generate pulse widths on the order of an optical cycle.