Publications by authors named "Nathaniel D Urban"

Potassium dihydrogen phosphate (KDP) and its deuterated analog (DKDP) are unique nonlinear optical materials for high power laser systems. They are used widely for frequency conversion and polarization control by virtue of the ability to grow optical-quality crystals at apertures suitable for fusion-class laser systems. Existing methods for freeform figuring of KDP/DKDP optics do not produce surfaces with sufficient laser-induced-damage thresholds (LIDT's) for operation in the ultraviolet portion of high-peak-power laser systems.

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Interactions of liquid crystals (LC's) with polarized light have been studied widely and have spawned numerous device applications, including the fabrication of optical elements for high-power and large-aperture laser systems. Currently, little is known about both the effect of incident polarization state on laser-induced-damage threshold (LIDT) and laser-induced functional threshold (LIFT) behavior at sub-LIDT fluences under multipulse irradiation conditions. This work reports on the first study of the nanosecond-pulsed LIDT's dependence on incident polarization for several optical devices employing oriented nematic and chiral-nematic LC's oriented by surface alignment layers.

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The presence of covalent tethers significantly enhanced the stability of structures consisting of helically arranged benzenetricarboxamide units that otherwise undergo very weak hydrogen-bonding interaction. The resultant molecular structures were probed by computational study, which predicted folded conformations consisting of helically arranged discs. Experimental studies confirmed the H-bonding interaction between the disk units, the monomeric nature of the corresponding molecules in solution, and the helical conformations of such molecules.

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