Duration-tunable high-energy picosecond pulsed optical fibre laser system and use of such laser system

An optical-fibre laser system comprising an injector suitable for generating at least one source pulse of duration between 30 and 100 picoseconds and having a source spectral bandwidth, a spectro-temporal shaping module arranged at the output of the injector, the spectro-temporal shaping module comprising a passive single-mode optical fibre having a length between 100 metres and 1 kilometre, the passive single-mode optical fibre having a physical length in metres that is between 6 and 12 times the duration of the source pulse in picoseconds, the spectro-temporal shaping module being configured to receive the source pulse and to generate a spectrally broadened pulse having a spectral bandwidth 5 to 50 times broader than the source spectral bandwidth and a duration of less than 1.5 times the source pulse duration, an optical amplifier system with flexible single-mode optical-fibre, the optical amplifier system having a flexible optical fibre length longer than one metre, the optical amplifier system comprising at least one last optical fibre amplifier, the last amplifier having a length of less than ten metres, at least one last spectral filter arranged downstream from the spectro-temporal shaping module and upstream from the last optical fibre amplifier, the last spectral filter having a spectral bandwidth of less than 50 nm and higher than or equal to the spectral bandwidth of the spectrally broadened light pulse, in such a way as to limit the generation of a Raman signal in the last optical-fibre amplifier, the last amplifier being suitable for receiving a filtered pulse from the spectral filter and for generating a controlled chirped amplified pulse at one end of the last amplifier, the end of the last optical-fibre amplifier being flexible about at least two axes of rotation transverse to the optical axis, with a minimum bending radius of less than 50 cm, the amplified pulse having an energy of more than 1 microjoule, a volume compressor attached to the end of the last optical-fibre amplifier, the compressor having a predetermined almost-linear chirp, the compressor being suitable for receiving the amplified pulse and forming a compressed pulse of less than 3 picoseconds duration, and electronic means for adjusting the compressed pulse duration, said electronic duration adjustment means being consisted of energy adjustment means suitable for adjusting the energy of the source pulse and/or of the amplified pulse, the duration of the compressed pulse being tunable based on the energy setting.