Davide

Peter: JC: Observation of high-order harmonic generation in a bulk crystal

http://www.nature.com/nphys/journal/v7/n2/full/nphys1847.html

Thoma: JC: Sub-cycle Oscillations in Virtual States Brought to Light

http://www.nature.com/srep/2013/130122/srep01105/full/srep01105.html?WT.ec_id=SREP-20130129

Johannes Floß: DM: Quantum resonance, Anderson localisation and selective rotational excitation in periodically kicked molecules

guest speaker: Johannes Floß, Department of Chemical Physics, Weizmann Institute of Science, Israel

The periodically kicked rotor has attracted much attention in the recent decades. In the classical regime the kicked rotor can exhibit truly chaotic motion, whereas in the quantum mechanical analogue, this chaotic motion is suppressed by Anderson-like localisation of the wave function in momentum space [1]. On the other hand, when the kicking period is equal to the rotational revival time, the kicked quantum rotor exhibits quantum resonance, an effect which leads to a linear increase of the angular momentum with the number of kicks [2]. Until today these phenomena were observed experimentally mainly in an atom optics analogue of a kicked rotor [3].

In this talk, I will provide an introduction to the two phenomena of quantum resonance and Anderson localisation in periodically kicked rotors. Then I will show how standard laser techniques used for molecular alignment provide a new way for observing these phenomena in a real rotor system, a diatomic molecule [4, 5]. I will also show that these phenomena provide a new toolbox for selective laser manipulations in molecular mixtures.

[1] S. Fishman, D. R. Grempel, and R. E. Prange, Phys. Rev. Lett. 49, 509 (1982).
[2] F. M. Izrailev and D. L. Shepelyanskii, Theor. Math. Phys. 43, 553 (1980).
[3] F. L. Moore, J. C. Robinson, C. Bharucha, B. Sundaraman, and M. G. Raizen, Phys. Rev.
Lett. 75, 4598 (1995).
[4] J. Floß and Ilya Sh. Averbukh, Phys. Rev. A 86, 021401 (R) (2012).
[5] J. Floß, S. Fishman, and Ilya Sh. Averbukh, arXiv 1305.5995 (2013).

Felicity: Extending HHG Spectroscopy to New Molecular Species

18 month transfer presentation. This presentation details the objectives of this PhD project and the current status of experiments. A review of the first apparatus which did yield Benzene HHG at 1500nm, albeit with limited success is presented along with the developments taken to construct the current apparatus. The acquisition of HHG spectra in a variety of molecules and ellipticity scans are presented along with impulsive alignment of the benzene molecule. The intended experiments which include the Jahn Teller Effect and PACER will be presnted and the possibility of working with other targets and spectroscopic methods will also be discussed.

William: DM: CEP 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, fewcycle pulse generation. Saturation of the output pulse energy is observed at 0:6 mJ for a 260µm inner-diameter,
1 m long fiber, statically filled with neon, with the pressure adjusted to achieve an output spectrum capable
of supporting sub-4 fs pulses. The maximum output pulse energy can be increased to 0:8 mJ 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

Dane: JC: Attosecond lighthouse

Original Lighthouse proposal / theory
http://prl.aps.org/abstract/PRL/v108/i11/e113904

Lighthouse in plasma mirror HHG:
http://www.nature.com/nphoton/journal/v6/n12/full/nphoton.2012.284.html

Lighthouse in gases:
http://www.nature.com/nphoton/journal/vaop/ncurrent/full/nphoton.2013.170.html