Development of ultra-stable characterization techniques for ultrashort laser beams

Resumen

The dramatic evolution that the laser science has undergone in the last six decades, and particularly in the field of ultrashort pulses, has been accompanied by breakthrough advances in the development of techniques for their characterization. Despite the large number of characterization techniques developed in the last two decades, it is still necessary to implement simpler and more robust techniques that can also operate in multiple spectral ranges. This Thesis is devoted to the study and development of temporal and spatiotemporal characterization techniques with compact and stable configurations, which are versatile, e.g., to analyze ultrashort laser beams with different temporal durations and in various spectral regions. The structure of this Thesis is made up of four main blocks. Firstly, a brief introduction to ultrafast optical metrology and the state of the art of spatial, temporal and spatiotemporal characterization techniques is presented in Part I. Then, Part II is focused on the review and extension of the capabilities of the amplitude swing temporal characterization technique, demonstrating three key advances: operation in different spectral regions from visible to near-infrared, with a tunability range spanning of more than one octave; characterization of ultrashort pulses in the few-cycle regime; or study of the implementation with different amplitude modulation schemes. In addition, a new retrieval algorithm is developed to analyze the amplitude swing traces based on differential evolution strategies. Thirdly, the fundamentals, operation range and experimental demonstration of a spatiotemporal characterization technique based on bulk lateral shearing interferometry are depicted in Part III. Furthermore, the technique is applied to characterize complex spatiotemporal couplings, like constant and time-varying optical vortices or the aberrations when focusing with astigmatic lenses. Finally, the main conclusions of the work and future perspectives are discussed in Part IV.