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Ultrashort laser pulses, ranging from a few to hundreds of femtoseconds, have become a revolutionary tool in various fields of science and technology. ⁤⁤These pulses have enabled the emergance of new scientific fields, such as femtochemistry, which investigates chemical reactions on a femtosecond timescale, and attosecond science, which explores subatomic motion on the attosecond scale. ⁤My research deals with two different aspects of ultrashort laser pulses: the temporal characterization and the manipulation of their temporal and polarization properties for new attosecond light sources.

Temporal characterization:

Applications of ultrafast laser sources often require an accurate characterization. ⁤⁤The dispersion scan technique, or d-scan, introduced in 2012 thanks to a collaboration between Lund and Porto universities, has become a widely used technique to measure the temporal profile of ultrashort laser pulses. ⁤⁤However, the d-scan method can only provide a measurement of an average pulse in a pulse train. ⁤⁤This limits its effectiveness in applications with significant variations between pulses, which are common in high-intensity laser systems. ⁤My project aims to develop the d-scan technique, allowing for individual pulse measurement while expanding its applicability across different wavelengths and pulse durations. ⁤⁤Besides new experimental implementations,  new computational methods such as artificial neutral networks will also be explored to enhance the pulse retrieval algorithm's speed. ⁤⁤The ultimate goal is to develop a robust and efficient technique capable of rapidly characterizing individual ultrashort laser pulses for any wavelenght and pulse duration.

Time-dependent polarization states for high-order harmonic generation:

Polarization gating is a well-known technique used to generate isolated attosecond pulses. By manipulating the temporal and polarization properties of ultrashort laser pulses, we aim at implementing an in-line set-up that enables the generation of single and double attosecond pulses with an adjustable delay. These pulses will open up new possibilities for studying the temporal dynamics of photoelectrons in gases.