Emma: JC: Controlling dielectrics with the electric field of light

Modern-day computing and optical communications are limited by the speed at which signals can be turned on and off. This paper demonstrates that frequencies of the order of Petahertz could be achieved by exploiting the change in behavior from insulator to conductor of a dielectric when exposed to strong, few-cycle laser pulses. Transient absorption, streaking and reflectivity techniques are used to probe these sub-femtosecond dynamics and observe the reversibility of the changes in the dielectric.
http://www.nature.com/nature/journal/v493/n7430/full/nature11720.html

paper:
http://www.nature.com/nature/journal/v493/n7430/pdf/nature11720.pdf

supplementary information:
http://www.nature.com/nature/journal/v493/n7430/extref/nature11720-s1.pdf

Davide: VUV double whammy

Extreme-ultraviolet pump–probe studies of one-femtosecond-scale electron dynamics

http://www.nature.com/nphys/journal/v7/n10/full/nphys2033.html

Observation of Ultrafast Charge Migration in an Amino Acid

http://pubs.acs.org/doi/abs/10.1021/jz3016028

and maybe a discussion of some first results?

Thomas: Manipulation of quantum paths for space–time characterization of attosecond pulses

Attosecond extreme-ultraviolet pulses1 have a complex space–time structure2. However, at present, there is no method to observe this intricate detail; all measurements of the duration of attosecond pulses are, to some extent, spatially averaged1, 3, 4, 5. A technique for determining the full space–time structure would enable a detailed study of the highly nonlinear processes that generate these pulses as a function of intensity without averaging6, 7. Here, we introduce and demonstrate an all-optical method to measure the space–time characteristics of an isolated attosecond pulse. Our measurements show that intensity-dependent phase and quantum-path interference both play a key role in determining the pulse structure. In the generating medium, the attosecond pulse is strongly modulated in space and time. Propagation modifies but does not erase this modulation. Quantum-path interference of the single-atom response, previously obscured by spatial and temporal averaging, may enable measuring the laser-field-driven ion dynamics with sub-cycle resolution.

http://www.nature.com/nphys/journal/vaop/ncurrent/full/nphys2525.html

Thomas' slides are here

Han: Generation of EUV radiation by plasmonic field enhancement using nano-structured bowties and funnel-waveguides

Generation of EUV radiation by plasmonic field enhancement using nano-structured bowties and funnel-waveguides

Recent experimental data of high-order harmonic generation (HHG), obtained by use of the plasmonic field enhancement of nanostructure bowties and funnel-waveguides, are presented. Emphasis is laid on reproduction of previous experimental results and also elucidation of the fundamental limitations associated with the nanostructure thermal damage, small laser-gas interaction volume, and atomic line emission in the plasmon-driven HHG process. In addition, the dominance of coherent harmonics is quantitatively verified by implementing a two-beam interference experiment using a pair of funnel-waveguides. This study proves that funnel-waveguides are a superior plasmonic device capable of providing not only high thermal immunity but also sufficient atom emitters to produce practically usable extreme-ultraviolet (EUV) radiation in a reproducible manner.

http://onlinelibrary.wiley.com/doi/10.1002/andp.201200160/abstract




Han's slides

Yusuke: HHG in aligned molecules with CEP-controlled pulses

High-order harmonics generated aligned molecules with CEP-controlled pulses are investigated. With short duration pulses harmonics are spectrally broadened due to non-adiabatic effect, which give rise to interferences between adjacent odd harmonics. The overlapped harmonics create interferences that become visible by locking the CEP. The interference contains the information of the phase of harmonics. We compare spectra generated with 25 fs pulses and spectra generated with 10 fs pulses. We have found some characteristics of the interference observing order dependence and molecular alignment dependence of the interference.

Simon: Efficient High Harmonic Generation

Discussion of phasematching aspects and recent experimental results from the attolab of HHG in capillaries and comparison to attotech style targets.

slides: http://charles.qols.ph.ic.ac.uk/~twitting/consJCDM/material/20121203_simon_hhg/121204%20Efficient%20High%20Harmonic%20Generation.pptx

Felicity: Spatiotemporal characterization of few-cycle laser pulses

In this paper we apply a broadband fiber optic coupler interferometer to the measurement of few-cycle laser pulses. Sub-8-fs pulses delivered by an ultrafast oscillator were characterized spatiotemporally using STARFISH, which is based on spatially resolved spectral interferometry. The reference pulse was measured with the d-scan technique. The pulses were focused by an off-axis parabolic mirror and were characterized at different transverse planes along the focusing region. The evolution of the retrieved pulses is analyzed, exhibiting small variations in the temporal (and spectral) amplitude and phase during propagation. Finally, the peak irradiance evolution is estimated from the integration of the spatiotemporal intensity.

http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-20-16-17880