[en] This thesis is devoted to the development of a technique for the measurement of the spatiotemporal amplitude and phase of ultrashort laser pulses and its applications. The core of the thesis is divided into three parts, which correspond to the presentation of the technique (Part I), its applications to diffractive optics (Part II) and to nonlinear optics and few-cycle pulses (Part III). Each part is divided into three chapters. The core of the thesis is preceded by an introductory chapter, which contains the scope and motivation of the thesis, the basic concepts about ultrashort laser pulses, and the state of the art of the already existing techniques for pulse characterization. Part I begins with a review of the temporal pulse characterization carried out by means of spectral interferometry (Chapter 2). Then, in Chapter 3, its extension to the spatial domain is introduced and, finally, in Chapter 4 we present the technique that we developed for spatiotemporal pulse characterization (STARFISH), which is based on a fiber optic coupler as part of the interferometer. In Part II, we will present its applications where diffractive optical elements in linear propagation regime are involved. This part covers the fundamentals of spatiotemporal coupling during propagation of pulses diffracted by a zone plate (Chapter 5), the application to a focusing kinoform diffractive lens, including the frequency-resolved wavefront measurement (Chapter 6), the production of fractal-shaped pulses and a dispersion compensated module for a diffraction grating (Chapter 7). The application to nonlinear processes and few-cycle pulses is discussed in Part III. In Chapter 8, we track the propagation dynamics of intense pulses under the regime of filamentation. Then, we present the application of STARFISH to few-cycle pulses delivered by an ultrafast oscillator (Chapter 9) and after post-compression of amplified pulses in a hollow-core fiber (Chapter 10). Finally, the main conclusions of this thesis are highlighted. The characteristics of the laser systems employed in the experiments are detailed in Appendix A

[es] En este resumen se pretenden mostrar los estudios realizados en el marco de la presente tesis. Por motivos de espacio, no se incluyen todos los resultados obtenidos que han sido presentados en los cap?tulos anteriores. El prop?sito de esta tesis es el desarrollo de una t?cnica para medir la amplitud y fase espaciotemporal de los pulsos l?ser ultracortos y sus aplicaciones. El n?cleo de la tesis se divide en tres partes, que corresponden a la presentaci?n de la t?cnica (R.2), las aplicaciones a ?ptica difractiva (R.3), a ?ptica no lineal y a pulsos de pocos ciclos ?pticos (R.4). En la Secci?n R.1 de introducci?n se presentan el marco y la motivaci?n de la tesis, los conceptos b?sicos sobre pulsos l?ser ultracortos, y el estado del arte de las t?cnicas ya existentes para la caracterizaci?n de los pulsos. La Secci?n R.2 comienza revisando la caracterizaci?n de pulsos por medio de interferometr?a espectral, para despu?s presentar la t?cnica que hemos desarrollado para la caracterizaci?n espaciotemporal de los pulsos (STARFISH), la cual se basa en un acoplador de fibra ?ptica como parte del interfer?metro. En la Secci?n R.3, presentamos las aplicaciones que involucran elementos ?pticos difractivos en r?gimen de propagaci?n lineal. Esta parte cubre los fundamentos del acoplamiento espaciotemporal durante la propagaci?n de pulsos difractados por una placa zonal (Cap?tulo 5), la aplicaci?n a una lente difractiva kinoforme incluyendo la medida del frente de ondas resuelto espectralmente. La aplicaci?n a procesos no lineales y a pulsos de pocos ciclos se presenta en la Secci?n R.4, en la que estudiamos la din?mica de la propagaci?n de pulsos intensos en el r?gimen de filamentaci?n. Posteriormente, se presenta la aplicaci?n de STARFISH a pulsos de pocos ciclos generados en un oscilador ultrarr?pido, y a continuaci?n, a la post-compresi?n de pulsos amplificados en una fibra hueca. Por ?ltimo, se resaltan las principales conclusiones de la tesis