Focused X-shaped pulses

Focused X-shaped pulses.

The space-time focusing of a (continuous) succession of localized X-shaped pulses is obtained by suitably integrating over their speed, i.e., over their axicon angle, thus generalizing a previous (discrete) approach. New superluminal wave pulses are first constructed and then tailored so that they become temporally focused at a chosen spatial point, where the wave field can reach very high inte...

Chirped optical X-shaped pulses in material media.

We analyze the properties of chirped optical X-shaped pulses propagating in material media without boundaries. We show that such ("superluminal") pulses may recover their transverse and longitudinal shapes after some propagation distance, whereas the ordinary chirped Gaussian pulses can recover their longitudinal width only (since Gaussian pulses suffer a progressive transverse spreading during...

Stimulated Emission Enhancement Using Shaped Pulses.

Controlling stimulated emission is of importance because it competes with absorption and fluorescence under intense laser excitation. We performed resonant nonlinear optical spectroscopy measurements using femtosecond pulses shaped by π- or π/2-step phase functions and carried out calculations based on density matrix representation to elucidate the experimental results. In addition, we compared...

Convergent-beam diffraction of ultra-short hard X-ray pulses focused by a capillary lens

We report the generation of diffraction patterns using X-ray pulses from a fs-laser plasma focused by an X-ray capillary lens to a spot size smaller than 100 μm. A thin moving iron tape is irradiated at 10 Hz with 200 mJ/130 fs titanium–sapphire laser pulses. Fe Kα (λ= 0.194 nm) radiation emitted from the rear side of the tape is focused to a spot by the capillary lens resulting in an intensity...

Coherent Control of spin-orbit precession with shaped laser pulses