Ultrafast lasers in the femtosecond regime : generation, amplification and measurement

Abstract : It is intuitive that with new tools to analyze nature, new domains can be explored. Ultrafast electromagnetic fields are one of those tools, as they allow the probing of matter on new time scales, both for new applications and for basic research. However they are on their own right an important phenomenon that deserves to be analyzed, studied and probed. This work is divided in two parts one that deals with the generation and amplification of ultrashort pulses the second with the diagnostics of these lasers. We present a home-built tunable, narrow spectrum CPA amplification chain. We study the features of optical parametric amplification in several configurations. We made simulations regarding the amplification of a seed pulse that is angularly chirped, we also make some analytical calculations based on the same principle. Two mode-locked oscillators are presented one is a sub-12 fs laser oscillator used to produce the seed of the amplification chain, the second is a sub-6 fs laser oscillator. We describe the first laser oscillator in great detail. We devise and discuss models that can explain the parameters of the sub-cavity and the ability of these lasers to enter into mode-locking (ML), we compare the simulation results precise experimental measures made on the sub-6 fs oscillator. The measurement of ultrafast phenomena is also very challenging because their time scale is too short for common electronic devices. We have examined known measurements, such as third order cross correlations (TOCC) and interferometric second order autocorrelations (IAC) and obtained new analysis methods and new facts that broaden their usefulness. In particular, we have fully reconstructed the spectral phase of a pulse using an IAC trace and its power spectrum. We also prove that the existence of a TOCC plus an intensity autocorrelation is sufficient to retrieve the intensity profile of a pulse we present initial results on reconstruction algorithms, that might be able to do this with a high temporal contrast. We end this thesis with a study on simulation and implementation of a new configuration for single shot correlation measurements.
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https://pastel.archives-ouvertes.fr/pastel-00942477
Contributor : Pedro Oliveira <>
Submitted on : Wednesday, February 5, 2014 - 9:14:00 PM
Last modification on : Wednesday, July 3, 2019 - 10:48:04 AM
Long-term archiving on : Sunday, April 9, 2017 - 9:37:43 AM

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Pedro Oliveira. Ultrafast lasers in the femtosecond regime : generation, amplification and measurement. Optics [physics.optics]. Ecole Polytechnique X, 2013. English. ⟨pastel-00942477⟩

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