Visible solid-state lasers in praseodymium-doped fluoride crystals

Since the first observation of the laser effect by Maiman in 1960, this invention has entered every aspect of our society in innumerable ways. From electronics to medicine, from industry to entertainment, the applications of lasers are everywhere: barcode scanners, disc players and recorders, trace gas detectors, bloodless surgery, lighting displays, cutting machines, printers, and countless more. But the laser has also contributed in developing scientific research, enabling new observation and fabrication methods, including spectroscopy, ablation, interferometry, deposition, and microscopy. Many of the previously cited applications require lasers in the visible region of the electromagnetic spectrum. The purpose of this work is to develop innovative solid-state lasers in the visible region, both to obtain laser emission at currently unavailable wavelengths, and to improve the efficiency, reliability, and compactness of existing sources. To pursue this goal, we employed trivalent praseodymium ion as active element, and fluoride crystals as host. This goal can be accomplished directly, by developing novel host materials and exploring their spectral features, and indirectly, by extending the operational range of already well-established materials, to achieve laser operation also on their weak emissions. In this work, we demonstrated indeed laser emission at previously unachieved wavelengths, improved the performance of some previously reported lasers, and succeeded in creating solid-state lasers based on innovative geometries. All these results are well detailed in the thesis, together with detailed descriptions of the methods employed to achieve them.