Advances in extreme nonlinear optics now make it possible to efficiently upshift femtosecond lasers into the ultraviolet (EUV) and soft X-ray regions of the spectrum, to wavelengths as short as 8 �. In an optimized geometry, the resultant high harmonics (HHG) emerge as fully spatially coherent beams, with ultra broad bandwidths supporting few-fs to attosecond pulses. This unique light source is ideally suited for capturing and controlling all dynamics relevant to function, from the attosecond timescales characteristic of electrons, to fs timescales characteristic of vibrations and dissociation, to ps timescales characteristic of rotations in molecules. Applications of ultrafast laser and HHG sources in materials, molecular and nano-systems will be presented.In recent work, we performed the first photoelectron spectroscopy of quantum dots in the gas phase, and also extracted how far the evanescent electron wavefunction extends from different size dots. This is a key property in understanding electronic coupling of nanoscale systems to their environment. Coherently manipulating the dynamics of electrons and ions in a molecule to steer the outcome of a chemical reaction is a long-standing goal in chemical science. However, broadband attosecond pulses cannot easily be used for state-selective electronic excitation and quantum control schemes. In recent work, we demonstrated that we can coherently manipulate multi-state electronic and multi-well nuclear dynamics, to control the ionization and dissociation channels of the only molecule where full modeling of the quantum dynamics is possible: hydrogen. Using VUV attosecond pulse trains and near-infrared light, we used interferences between electronic wave packets to select the electronic state of the neutral molecule, and then switch it on attosecond timescales.Finally, HHG can also capture the correlated motions of electrons and nuclei that lies at the heart of radiation chemistry.

Probing electron dynamics in molecules, quantum dots, and materials at the space-time limits using coherent tabletop high harmonic X-rays

246th National Meeting (2013)

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