Search results for "Ultrashort pulses"
showing 3 items of 3 documents
Parallel laser micromachining based on diffractive optical elements with dispersion compensated femtosecond pulses
2013
We experimentally demonstrate multi-beam high spatial resolution laser micromachining with femtosecond pulses. The effects of chromatic aberrations as well as pulse stretching on the material processed due to diffraction were significantly mitigated by using a suited dispersion compensated module (DCM). This permits to increase the area of processing in a factor 3 in comparison with a conventional setup. Specifically, 52 blind holes have been drilled simultaneously onto a stainless steel sample with a 30 fs laser pulse in a parallel processing configuration.
'SMART laser', Development of laser sources integrating an optimized functioning via a process of learning
2022
Ost commercially available mode-blocking lasers provide a unique pulse regime to the user, driven only by a simple switch. To solve certain problems, it would be advantageous to increase the possibilities of pulse adjustment in many areas of application, from micro-machining to wavelength conversion. One way to increase the degrees of freedom of a laser cavity is to incorporate into it a saturable absorbant with adjustable parameters, as with non-linear polarization evolution devices (NPEs). The absence of an analytical relationship between the adjustable cavity parameters and the characteristics of a generated pulse can be circumvented by the use of scalable algorithms, well suited to mult…
Alignement moléculaire par impulsions laser ultrabrèves : Mesures & Applications
2009
The interaction of an intense ultrashort laser pulse with a molecular sample leads, after the end of the pulse, to molecular alignment at specific time under field-free conditions. This thesis is dedicated to the measurements and applications of this effect. The degree of alignment is determined through the variation of the refractive index induced by the rearrangement of the molecular dipoles. A two-dimensional technique allowing to measure molecular alignment on a single-shot basis is reported in this document. The alignment is then exploited in order to determine physical quantities which are usually difficult to estimate through others methods. The "cross-defocusing technique" has been …