451 research outputs found
Infrared attosecond field transients and UV to IR few-femtosecond pulses generated by high-energy soliton self-compression
Infrared femtosecond laser pulses are important tools both in strong-field
physics, driving X-ray high-harmonic generation, and as the basis for widely
tuneable, if inefficient, ultrafast sources in the visible and ultraviolet.
Although anomalous material dispersion simplifies compression to few-cycle
pulses, attosecond pulses in the infrared have remained out of reach. We
demonstrate soliton self-compression of 1800 nm laser pulses in hollow
capillary fibers to sub-cycle envelope duration (2 fs) with 27 GW peak power,
corresponding to attosecond field transients. In the same system, we generate
wavelength-tuneable few-femtosecond pulses from the ultraviolet (300 nm) to the
infrared (740 nm) with energy up to 25 J and efficiency up to 12 %, and
experimentally characterize the generation dynamics in the time-frequency
domain. A compact second stage generates multi-J pulses from 210 nm to 700
nm using less than 200 J of input energy. Our results significantly expand
the toolkit available to ultrafast science.Comment: 8 pages, 5 figure
High-energy ultraviolet dispersive-wave emission in compact hollow capillary systems
We demonstrate high-energy resonant dispersive-wave emission in the deep
ultraviolet (218 to 375 nm) from optical solitons in short (15 to 34cm) hollow
capillary fibres. This down-scaling in length compared to previous results in
capillaries is achieved by using small core diameters (100 and 150 m) and
pumping with 6.3 fs pulses at 800 nm. We generate pulses with energies of 4 to
6 J across the deep ultraviolet in a 100 m capillary and up to 11
J in a 150 m capillary. From comparisons to simulations we estimate
the ultraviolet pulse to be 2 to 2.5 fs in duration. We also numerically study
the influence of pump duration on the bandwidth of the dispersive wave.Comment: 5 pages, 3 figure
Physics Revealed at Intermediate p_T
A review is given on the subject of hadron production at intermediate
in heavy-ion collisions. The underlying dynamical processes are inferred from
interpreting the data in the framework of recombination. Ridge formation with
or without triggers is found to play an important role in nearly all
observables in that region. Correlation data would be hard to interpret
without taking ridges into account. The semi-hard partons that create the
ridges may even be able to drive elliptic flow without fast thermalization.Comment: 8 pages, plenary talk given at Quark Matter 2008, Jaipur, Indi
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