Macroscopic effects in noncollinear high-order harmonic generation.

We study two-color high-order harmonic generation using an intense driving field and its weak second harmonic, crossed under a small angle in the focus. Employing sum- and difference-frequency generation processes, such a noncollinear scheme can be used to measure and control macroscopic phase matching effects by utilizing a geometrical phase mismatch component, which depends on the noncollinear angle. We further show how spatial phase effects in the generation volume are mapped out into the far field allowing a direct analogy with temporal carrier envelope effects in attosecond pulse generation.

A high-flux high-order harmonic source.

We develop and implement an experimental strategy for the generation of high-energy high-order harmonics (HHG) in gases for studies of nonlinear processes in the soft x-ray region. We generate high-order harmonics by focusing a high energy Ti:Sapphire laser into a gas cell filled with argon or neon. The energy per pulse is optimized by an automated control of the multiple parameters that influence the generation process.

Efficient high-order harmonic generation boosted by below-threshold harmonics.

High-order harmonic generation (HHG) in gases has been established as an important technique for the generation of coherent extreme ultraviolet (XUV) pulses at ultrashort time scales. Its main drawback, however, is the low conversion efficiency, setting limits for many applications, such as ultrafast coherent imaging, nonlinear processes in the XUV range, or seeded free electron lasers. Here we introduce a novel scheme based on using below-threshold harmonics, generated in a "seeding cell", to boost the HHG process in a "generation cell", placed further downstream in the focused laser beam.

Sequential single-shot imaging of nanoscale dynamic interactions with a table-top soft x-ray laser.

We demonstrate the first real-space recording of nanoscale dynamic interactions using single-shot soft x-ray (SXR) full-field laser microscopy. A sequence of real-space flash images acquired with a table-top SXR laser was used to capture the motion of a rapidly oscillating magnetic nanoprobe. Changes of 30 nm in the oscillation amplitude were detected when the nanoprobe was made to interact with stray fields from a magnetic sample.

Extreme ultraviolet laser-based table-top aerial image metrology of lithographic masks.

We have realized the first demonstration of a table-top aerial imaging microscope capable of characterizing pattern and defect printability in extreme ultraviolet lithography masks. The microscope combines the output of a 13.2 nm wavelength, table-top, plasma-based, EUV laser with zone plate optics to mimic the imaging conditions of an EUV lithographic stepper.

Microscopy of extreme ultraviolet lithography masks with 13.2 nm tabletop laser illumination.

We report the demonstration of a reflection microscope that operates at 13.2 nm wavelength with a spatial resolution of 55+/-3 nm. The microscope uses illumination from a tabletop extreme ultraviolet laser to acquire aerial images of photolithography masks with a 20 s exposure time.

Single-shot extreme ultraviolet laser imaging of nanostructures with wavelength resolution.

We have demonstrated near-wavelength resolution microscopy in the extreme ultraviolet. Images of 50 nm diameter nanotubes were obtained with a single ~1 ns duration pulse from a desktop-size 46.9 nm laser.

Sub-38 nm resolution tabletop microscopy with 13 nm wavelength laser light.

We have acquired images with a spatial resolution better than 38 nm by using a tabletop microscope that combines 13 nm wavelength light from a high-brightness tabletop laser and Fresnel zone plate optics. These results open a gateway to the development of compact and widely available extreme-ultraviolet imaging tools capable of inspecting samples in a variety of environments with a 15-20 nm spatial resolution and a picosecond time resolution.

Capillary discharge-driven metal vapor plasma waveguides.

We report the generation of dense plasma waveguides containing a large concentration of silver ions by means of a fast (approximately 55 ns first half-cycle) microcapillary discharge. Concave plasma density profiles with axial electron density > 1 x 10(19) cm(-3) were measured from discharge ablation of 330 or 440 microm diameter Ag2S capillaries with 3-5 kA peak amplitude current pulses. The dynamic of this plasma waveguide was studied with interferometry, absorption measurements, and hydrodynamic model simulations.

Nanoimaging with a compact extreme-ultraviolet laser.

Images with a spatial resolution of 120-150 nm were obtained with 46.9 nm light from a compact capillary-discharge laser by use of the combination of a Sc-Si multilayer-coated Schwarzschild condenser and a free-standing imaging zone plate. The results are relevant to the development of compact extreme-ultraviolet laser-based imaging tools for nanoscience and nanotechnology.

Reflection mode imaging with nanoscale resolution using a compact extreme ultraviolet laser.

We report the demonstration of reflection mode imaging of 100 nm-scale features using 46.9 nm light from a compact capillary-discharge laser. Our imaging system employs a Sc/Si multilayer coated Schwarzschild condenser and a freestanding zone plate objective.

[Hypertensive cardiopathy. Phonomechanocardiographic study and review of its physiopathological mechanisms].

Sixty four patients with essential hypertension were studied by phonocardiographic systolic time intervals. Prolongation of the pre-ejection period (PEP) at expense of the isovolume contraction time and of the true isovolume contraction time, which suggests myocardial contractile depression due to the increase in after-load. The significant increase, in rise of mean velocity of ventricular pressure suggests that the Anrep phemomena is used by the human heart as a compensatory mechanism in systemic hypertension.