High Energy 10 fs Pulses by a New Pulse Compression Technique

A well established method for the generation of ultrashort pulses is optical pulse compression, which consists in spectral broadening by self-phase modulation in a single-mode optical fiber followed by chirp compensation into suitable phase dispersive elements. In this way pulses as short as 6 fs have been obtained [1]. The use of single-mode fibers is limited to low energy (nanojoule) pulses due to both material damage and appearance of high-order nonlinearities. So far spectral broadening of high energy femtosecond pulses was achieved in bulk materials [2] where the non-uniform transverse intensity profile of the beam represents a limitation. A compression technique for high energy ultrashort pulses must have a large diameter single mode guiding element with sufficiently high damage threshold and very fast third order non-linear optical susceptibility.