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Browsing by Author "Marconi, Mario, advisor"

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    Development of a very compact high repetition rate soft x-ray laser
    (Colorado State University. Libraries, 2010) Furch, Federico Juan Antonio, author; Rocca, Jorge J., advisor; Marconi, Mario, advisor
    Over the last 25 years, the field of soft x-ray lasers has evolved from facility size devices delivering a few shots per day, to table-top lasers operating at several shots per second. In these lasers the gain medium is a highly ionized, hot and dense plasma created by a sequence of short, high energy pulses from an optical laser. Current table-top soft x-ray lasers have enabled numerous applications such as nano-scale imaging, nano-fabrication and dense plasma diagnosis among others. However these lasers are still limited in repetition rate, and therefore average power, owing to thermal effects originated in the flash lamp pumped amplifiers of the optical driver laser. Direct diode-pumping of the driver laser opens the possibility of developing more compact, higher repetition rate optical laser systems to pump soft x-ray lasers. Directly pumping small quantum defect materials such as Yb:YAG with a narrow bandwidth source of the optimum wavelength allows to significantly increase the efficiency and then reduce the thermal load in the gain materials. In addition, cryogenic cooling of the laser materials significantly improves their thermal performance. This approach will allow for soft x-ray laser operation at much higher repetition rates. In this work I present the results of the demonstration of an all diode-pumped soft x-ray laser that constitutes the first of a new generation of more compact, higher repetition rate soft x-ray lasers in the spectral region between 10 and 20 nm. To pump these lasers we developed an all diode-pumped chirped pulse amplification laser system based on cryogenically cooled Yb:YAG. This optical laser generates pulses of 1 J of energy in 8.5 ps pulses at 10 Hz, the highest energy per pulse for sub-10 ps pulses from a diode-pumped system at the present time. This soft x-ray laser has the potential to operate at unsurpassed repetition rates in a reduced footprint.
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    FLASH holographic microscopy using a compact extreme ultraviolet table top laser
    (Colorado State University. Libraries, 2015) Monserud, Nils C., author; Marconi, Mario, advisor; Menoni, Carmen, committee member; Wu, Mingzhong, committee member
    Microscopes allow our eyes to visualize objects at micro- and nanoscales. But there application are not limited to static images. The visualization of dynamic processes is necessary to understand complex systems on the micro- and nanoscales, Thus the need for microscopes capable of visualizing nanoscale processes, to further extend the development on micro- and nano-electromechanical devices (MEMS and NEMS). Conventional microscopy will not be sufficient for this purpose for two reasons the first is the spatial resolution is not sufficient to capture nanoscale objects and secondly if the object is moving out of plane the image taken needs to be adjusted using methods of post processing. To this end Fourier transform holography using and EUV light source was utilized to provide us with a method recording sub-micron oscillators. We recorded the oscillation of sub-micron pillars using time resolved extreme ultraviolet (EUV) Fourier transform Holography. The source utilized was a 46.9 nm tabletop capillary discharge with an EUV wavelength of 46.9nm, which provided large flux of coherent illumination. The bright illumination allowed for a modified Fresnel Zone plate to be used as a beam splitter. The modified Fresnel zone plate was able to produce a reference and object beam. This reference and object beam interfered creating a hologram. The reference wave is created by the first order focus while a central opening in the zone plate illuminates the object. Single-shot holograms allowed for the composition of a movie featuring the fast oscillation. Three-dimensional displacements of the object were determined as well by numerical back-propagation, or "refocusing" of the electromagnetic fields during the reconstruction of a single holography.