Synopsis: The interference of attosecond electron wavepackets, created by high harmonic and femtosecond laser pulses, is measured. The first electron wavepacket is generated by direct ionization of He, and the second one by the two step process of resonant excitation by the attosecond high harmonic pulse and subsequent ionization by the laser pulse. The amplitude and phase retrieved from the in...

Ionization-assisted spectral broadening of high-energy 10.6 μm laser pulses in a gas-filled hollow waveguide is shown to yield single-cycle pulses with multiterawatt peak powers in the mid-IR. While the highest quality of pulse compression is achieved in the regime of weak ionization, careful management of complex ionization-assisted spectral broadening of guided-wave fields is the key to compr...

Atoms undergoing strong-field ionization in two-color circularly polarized femtosecond laser fields exhibit unique two-dimensional photoelectron trajectories and can emit bright circularly polarized extreme ultraviolet and soft-x-ray beams. In this Letter, we present the first experimental observation of nonsequential double ionization in these tailored laser fields. Moreover, we can enhance or...

Mass spectrometry proteomic profiling has potential to be a useful clinical screening tool. One obstacle is providing a standardized method for preprocessing the noisy raw data. We have developed a system for automatically determining a set of preprocessing methods among several candidates. Our system's automated nature relieves the analyst of the need to be knowledgeable about which methods to...

Proteomic analysis offers great diagnostic relevance, because unlike DNA, different cells in an organism express different proteins. In fact, the cellular proteome can vary as a function of time or in response to stimuli. Beyond amino acid sequence, protein function depends on chemical modifications known as posttranslational modifications (PTMs) that serve as “switches” and “signals” that acti...

Changes in the laser induced molecular dissociation of 1,1,1-trichloroethane (TCE) were studied using a range of intensities and standard laser wavelengths with nanosecond and femtosecond pulse durations. TCE contains C-H, C-C and C-Cl bonds and selective bond breakage of one or more of these bonds is of scientific interest. Using laser ionization time of flight mass spectrometry, it was found ...

We report an original optical method providing the probability of molecular ionization induced by femtosecond laser pulses. The approach consists of exploiting molecular alignment to extract reliable information about ionization. The cross defocusing technique implemented for this purpose reveals a sensitivity with respect to postpulse alignment, as well as to the free electron density induced ...

The kinetic energy spectra of D+ ions resulting from the sequential double ionization of D2 molecules in an intense few-cycle laser field are calculated. The D2 molecule is first ionized at its equilibrium distance, followed by further ionization of D2 + at larger internuclear separations. The time evolution of the nuclear wave packet is calculated including loss from ionization by the time-dep...

When intense laser pulses release electrons nonsequentially, the time delay between the last recollision and the subsequent ionization may last longer than what is expected from a direct impact scenario [recollision excitation with subsequent ionization (RESI)]. We show that the resulting delayed ionization stems from the inner electron being promoted to a sticky region. We identify the mechani...