This research project focuses on understanding and reducing thermal noise and upconversion noise in Intermediate and Advanced LIGO. These noise sources are the limiting ones in LIGO's central frequency range of 40 - 400 Hz. Thus their reduction has a direct positive impact on LIGO's sensitivity and expected event rate. The PI will explore the fundamental limits to the loss in fused silica and the practically achievable loss limits required for the Advanced LIGO optics. He will investigate new methods and materials for reducing the loss in the mirror coatings for Advanced LIGO. He will explore improved suspension methods for Intermediate LIGO, to see if a modest change may improve LIGO's sensitivity in time for Science Run 6. He will also begin design studies for test mass mirror configuration for third generation gravity wave observatories. Finally he will continue development of a bicoherence monitor to provide a means for detecting upconversion noise, which has become an increasingly important noise source in Initial LIGO. LIGO's success is dependent upon its ability to increase its sensitivity sufficiently to detect gravity waves and to do so at a rate worthy of a true astronomical observatory. The most direct path toward that goal is to reduce the limiting noise sources in LIGO's most sensitive central frequency region. The PI's research is directed precisely at that goal. In addition, the PI's work is conducted at a small liberal arts college, which has allowed undergraduate and even high school students to get involved in this research. In addition the PI also commits significant efforts to public education and international cooperation. He gives a few public lectures each year; he organized the first joint technical meeting between the LIGO and Virgo collaborations; and he serves on the Executive Committee of the American Physical Society's Topical Group on Gravitation.
