Theoretical Concepts for Generation and Characterization of Ultraviolet Laser Pulses

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The ultraviolet region is an important part of the electromagnetic spectrum since excitation and ionization energies of many atoms, molecules, nanoparticles, and materials lie in this spectral regime. Light sources operating at ultraviolet wavelengths can be used to trigger, steer, probe, and image physical processes, chemical reactions and transitions in materials on ultrafast time scales. Beyond their significance for fundamental scientific research, applications of ultraviolet lasers can be found in nanotechnology, microlithography and micromachining, medicine and other areas. Applications and interpretation of scientific results are however still limited due to a lack of bright tunable light sources generating well-characterized short pulses at ultraviolet wavelengths. Research in this project will promote the progress of science in this area by developing and applying new theoretical methods to understand aspects of the generation of short-pulsed ultraviolet laser light and to measure the generated ultrashort pulses in experiments. A graduate student will receive training in a forefront topic in theoretical atomic, molecular, and optical physics. This includes the analysis of concepts towards the project goals, the development of software and its applications, as well as the dissemination of the results in oral and written form. The focus of this project is to provide theoretical support for the development of short-pulsed ultraviolet laser sources. To this end, numerical simulations of the macroscopic high harmonic generation in a gas jet experiment will be performed. Specific emphasis will be given to the analysis of the impact of the spatial phase dependence across the laser focus of a short Gaussian laser pulse generating the harmonic response. Conditions for good coherent build-up of harmonic radiation will be identified and the influence of experimental limitations, such as fluctuations in laser intensity or gas density, will be analyzed. Furthermore, a multi-Gaussian auto- and cross-correlation approach and its application to various pulse forms will be investigated.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.