The activities supported by this award will expand and strengthen the partnership in materials research between Southern University and the Laser Interferometer Gravitational-wave Observatory (LIGO). Detailed chemical and micro-structural information on multilayer coatings for use in Advanced LIGO test mass mirrors will be provided. Correlations will be examined between the physical properties of the coatings and their mechanical loss factors. Potential correlations between microscopic features of surface morphology and light scattering will also be studied. Southern University's newly acquired atomic force microscope (AFM) will provide valuable two- and three-dimensional images of the multilayer mirror coatings showing features of the surface morphology at or near the nanometer level. Faculty and students will also use the local CAMD synchrotron radiation source to determine the detailed elemental composition and molecular features of the multilayers through the use of X-ray absorption spectroscopy methods. X-ray fluorescence (XRF), X-ray Near Edge Structure (XANES) and Extended X-ray Absorption Fine Structure (EXAFS) will be employed to obtain information on chemical composition, valence and charge transfer, bond lengths and number and type of nearest neighbors. Complementary X-ray diffraction measurements will also be performed on the samples to examine the degree of crystallinity within the multilayers. The proposed research is new and directly supports the realization of Advanced LIGO. Currently, mechanical noise in coating will limit the projected sensitivity of Advanced LIGO. While the best coatings achieved to date are expected to be adequate to achieve design sensitivity, any improvement in coatings will increase Advance LIGO's ultimate sensitivity and correspondingly the volume of the universe within its reach. This award enables graduate and undergraduate students at Southern University to participate meaningfully in forefront scientific research.
