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Photoelectron and photoion spectroscopy of atoms, molecules, nanoparticles, and nanoplasmas irradiated with strong femtosecond laser fields

Event Details

Event Dates: 

Wednesday, November 12, 2014 - 2:00pm

Seminar Location: 

  • JILA 10th Floor

Speaker Name(s): 

Dan Hickstein

Speaker Affiliation(s): 

JILA, Kapteyn & Murnane group
Seminar Type/Subject

Scientific Seminar Type: 

  • JILA Thesis Defense

Event Details & Abstract: 

Modern femtosecond lasers can produce pulses of light that are shorter than the vibrational periods in molecules and generate electric fields stronger than the Coulomb force that binds electrons in atoms. These short pulse lasers enable us to observe chemical reactions, produce attosecond bursts of high-energy photons, and precision-machine solid materials without heat transport to the material. In this thesis, I describe three experiments that provide new insight into strong-field (~1014 Watts/cm2) femtosecond laser-matter interactions in three important regimes. First, I discuss the strong-field ionization of gas-phase atoms and molecules, identify a new structure in the photoelectron angular distribution of xenon gas, and explain this structure as a result of electrons colliding with the Coulomb potential of the ion. Second, I describe a new method to perform photoelectron and photoion spectroscopy on single, isolated nanoparticles and demonstrate this technique by observing and controlling shock waves in nanoplasmas. Finally, I demonstrate that laser pulses near the ablation threshold can be used to induce highly localized ablation in a single nanostructure, and how the direction of subsequent ion ejection provides a map of nanoscale field enhancement. These findings will guide future efforts to probe the structure of atoms and molecules on the femtosecond timescale, produce high-energy ions from plasma, and design nanomaterials that enhance light on the subwavelength scale.

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