RESUMO
Two-stage multipass-cell compression of a fiber-chirped-pulse amplifier system to the few-cycle regime is presented. The output delivers a sub-2-cycle (5.8â fs), 107â W average power, 1.07â mJ pulses at 100â kHz centered at 1030â nm with excellent spatial beam quality (M2 = 1.1, Strehl ratio S = 0.98), pointing stability (2.3â µrad), and superior long-term average power stability of 0.1% STD over more than 8â hours. This is combined with a carrier-envelope phase stability of 360â mrad in the frequency range from 10â Hz to 50â kHz, i.e., measured on a single-shot basis. This unique system will serve as an HR1 laser for the Extreme Light Infrastructure Attosecond Light Pulse Source research facility to enable high repetition rate isolated attosecond pulse generation.
RESUMO
We report on the successful implementation of an adaptive pre-amplification pulse shaping technique in a high-power, coherently combined fiber laser system to achieve sub-300-fs pulse durations at 320 W average power and 3.2 mJ pulse energy. The pulse shaper is utilized to impose a gain flattening mask to increase the spectral width of the amplified pulse by 60%. Simultaneously, it pre-compensates the spectral phase acquired in the multi-stage amplification and subsequent compression including the eight-channel, coherently combined main amplification stage. This result does significantly enhance the performance of the fiber laser system and the subsequent nonlinear compression stages.
RESUMO
We report on the characteristics of an active fiber with core material made by sintering of Yb-doped silica powders as an alternative to a conventional modified chemical vapor deposition (MCVD) technique. This material provides the possibility to design very large and homogenously rare-earth doped active fiber cores. We have determined a fiber background attenuation of 20 dB/km and measured a slope efficiency of 80%. These values are comparable to established fibers made by MCVD technology.