Sökresultat

We present temporal characterization of attosecond pulse trains generated during selfguided propagation of intense pulses in a long gas target. Spectral phase jumps are observed, affecting the temporal shape of the attosecond pulse train.

Huge dynamic Stark shifts of atomic energy levels in xenon induced by high-intensity laser light have been measured by a new method based upon multiphoton ionization by a tunable femtosecond laser source. Stark-induced multiphoton resonances appear as identifiable structures in the photoelectron energy spectra. The change in the structures positions, when the photon energy is tuned, is directly re

Type 2 diabetes (T2DM) is associated with pancreatic islet dysfunction. Loss of β-cell identity has been implicated via dedifferentiation or conversion to other pancreatic endocrine cell types. How these transitions contribute to the onset and progression of T2DM in vivo is unknown. The aims of this study were to determine the degree of epithelial-to-mesenchymal transition occurring in α and β cel

We present the carrier-envelope phase dependent high-order harmonic generation in argon at 200 kHz repetition rate using ultra-short laser pulses from an optical parametric chirped pulse amplifier.

Pancreas transplantation is a successful treatment for a selected group of people with type 1 diabetes. Continued insulin production can decrease over time and identifying predictors of long-term graft function is key to improving survival. The aim of this study was to screen subjects for variation in the Caveolin-1 gene (Cav1), previously shown to correlate with long-term kidney transplant functi

BACKGROUND: Chronic kidney disease (CKD) is associated with accelerated cardiovascular disease and heart failure. Endothelial nitric oxide synthase (eNOS) Glu298Asp single nucleotide polymorphism (SNP) genotype has been associated with a worse phenotype amongst patients with established heart failure and in patients with progression of their renal disease. The association of a cardiac functional d

PURPOSE:To develop a phantom for validating MRI pulse sequences and data processing methods to quantify microscopic diffusion anisotropy in the human brain.METHODS:Using a liquid crystal consisting of water, detergent, and hydrocarbon, we designed a 0.5-L spherical phantom showing the theoretically highest possible degree of microscopic anisotropy. Data were acquired on the Connectome scanner usin

CONTEXT: Viral/bacterial infection is proposed as a trigger for the autoimmune thyroid diseases (AITD): Graves' disease (GD) and Hashimoto's thyroiditis (HT). Previous studies in European Caucasian AITD subjects found higher birth rates in the autumn/winter, suggesting those born in the autumn/winter experience increased viral/bacterial exposure after birth, impacting upon immune system developmen

We demonstrate theoretically and experimentally a robust method based on sequential filamentation to optimize compression of high-energy pulses in gases. We gain insight into this process by comparing compression dynamics for linear- and circularly-polarized pulses.

Attosecond extreme ultraviolet light pulses have the potential to resolve the ultrafast electron dynamics that govern basic properties of atoms, molecules, and solids. Here we present three different interferometric pump-probe methods aiming to access not only the temporal dynamics, but also state specific phase information after excitation/ionization using attosecond pulses.

2.5 TW laser pulses at 1053 nm are obtained in a compact set-up, from chirped pulses, successively stretched, amplified up to 1.6 J and compressed to 0.6 ps, at a repetition rate of one shot per minute.

We will present the new Lund HHG beamline designed for high photon flux, delivering pulse energies of more than 4 μJ per pulse in the spectral range from 20 eV to 45 eV. Focused XUV intensities above 1014 W/cm2 should become possible.

We investigate the performance of the recently introduced 'd-scan' technique for the characterization of ultrashort laser pulses by comparing it with a well-established technique (SPIDER). Good agreement is obtained from the two different measurements.

We present different approaches for high repetition rate, few-cycle pulse generation with μJ-level energy from compact OPCPA systems. The sources are based on octave spanning Ti:Sa oscillators with all-optical synchronization to state-of-the-art Ytterbium based amplifiers.

The confinement of high-harmonic-generation pulse train by modulation of the fundamental beam polarization is studied temporaly and spectrally. We observe a clear effect, beeing the maximal confinement compatible with 1-or-2 subfemtosecond pulse emission.

A compact, high-repetition rate OPCPA system with CEP-stable 6.3 fs pulses duration and 10 μJ of pulse energy is presented together with results from numerical simulations. First results of high harmonic generation will be shown.

We demonstrate a dispersion-free split mirror interferometric autocorrelator suitable for measuring pulses with durations from hundreds of attoseconds to tens of femtoseconds and spectral content from the near-UV to near-IR.