High-contrast Ultrabroadband Frontend Source for High Intensity Few-Cycle Lasers

An ultrabroadband seed source for high-power, high-contrast OPCPA systems at 800 nm is presented. The source is based on post compression in a hollow-core fiber followed by crossed polarized waves (XPW) filtering and is capable of delivering 80$\mu$J, 5fs, CEP-stable (0.3rad RMS) pulses with excellent spectral and temporal qualit

Passive coherent combining of CEP-stable few-cycles pulses from a temporally divided hollow fiber compressor

International audienceWe demonstrate a simple and robust passive coherent combining technique for temporal compression of millijouleenergy laser pulses down to few-cycle duration in a gas-filled hollow fiber. High combining efficiency is achieved byusing carefully oriented calcite plates for temporal pulse division and recombination. Carrier-envelope phase (CEP)-stable, 6-fs, 800-nm pulses with more than 0.6 mJ energy are routinely generated. This method could aid in theenergy scaling of CEP-stable hollow-fiber compressor systems

Carrier-envelope phase stability of hollow-fibers used for high-energy, few-cycle pulse generation

We investigated the carrier-envelope phase (CEP) stability of a hollow-fiber setup used for high-energy, few-cycle pulse generation. Saturation of the output pulse energy is observed at 0.6 mJ for a 260 um inner-diameter, 1 m long fiber, statically filled with neon, with the pressure adjusted to achieve an output spectrum capable of supporting sub-4fs pulses. The maximum output pulse energy can be increased to 0.8mJ by using either differential pumping, or circularly polarized input pulses. We observe the onset of an ionization-induced CEP instability, which does not increase beyond an input pulse energy of 1.25 mJ due to losses in the fiber caused by ionization. There is no significant difference in the CEP stability with differential pumping compared to static-fill, demonstrating that gas flow in differentially pumped fibers does not degrade the CEP stabilization.Comment: 4 pages, 4 figure

Efficient cross polarized wave generation for compact, energy-scalable, ultrashort laser sources

International audienceThe generation of high contrast and ultrashort laser pulses via a compact and energy-scalable cross polarized wave filter is presented. The setup incorporates a waveguide spatial filter into a single crystal XPW configuration, enabling high energy and high intensity transmission, efficient contrast enhancement and pulse shortening at the multi-mJ level. Excellent XPW conversion of up to 33% (global efficiency: 20%, intensity transmission: 40%) led to an output energy of 650 ?J for an input of 3.3 mJ. Additionally, efficient conversion under specific input phase conditions, allowed pulse shortening from 25 fs to 9.6 fs, indicating the prospective application of this setup as a high energy, ultrabroad laser source. © 2010 Optical Society of America

Energy-scalable temporal cleaning device for femtosecond laser pulsesbased on cross-polarized wave generation

International audienceWe report on a compact energy-scalable device for generating high-fidelity femtosecond laser pulses based on spatial filtering through a hollow-core fiber followed by a nonlinear crystal for crosspolarized wave (XPW) generation. This versatile device is suited for temporal pulse cleaning over a wide range of input energies (from 0.1 to >10 mJ) and is successfully qualified on different ultrafast laser systems. Full characterization of the XPW output is presented. In particular, we demonstrate the generation of 1.6 mJ energy pulses starting from 11 mJ input pulse energy. The temporal contrast of the pulses is enhanced by more than 4 orders of magnitude. In addition, pulse shortening from 40 fs down to 15 fs Fourier-transform limit yields an overall peak-power transmission of up to 50%. This device not only serves as an integrated pulse contrast filter inside an ultrafast laser amplifier but also as a simple back-end solution for temporal post-compression of amplified pulses