Spatial characterization of light beams analyzed by cylindrical-grating slit-less spectrometers.

In this work, we theoretically analyze the spatial information provided by cylindrical-grating slit-less spectrometers. We raise attention on the often not considered property that the spatial features acquired using these spectrometers are different from what can be obtained using a spectrometer with an entrance slit. In relation to this, we also highlight that they do not provide information directly on the real spatial beam profile.

Carrier-envelope phase changes in the focal region: propagation effects measured by spectral interferometry.

Spectral interferometric measurements are presented that show how wave propagation affects the carrier-envelope phase (CEP) of an ultrashort pulse in the focal region and results in variations that are different from the Gouy phase shift. Wavelength-dependent properties of the input beam are investigated and are seen to influence how the CEP is altered. The measured CEP changes show characteristics similar to the variations predicted by theory.

Rotation of the polarization direction and reversal of helicity of ultrashort pulsed beams propagating in free space.

We unveil the origin of the recently revealed polarization-state changes of polarization-shaped few-cycle pulses induced by free-space beam propagation. Simple rules are formulated to show how the orientation and ellipticity of the instantaneous polarization ellipse of the source and propagated pulses relate to each other. We demonstrate our findings with examples that clearly display the relationships found and highlight their relevance.