Gravitational Wave Seminar Series: “Internal Friction: The history of LIGOs thermal noise research”

The Syracuse University Physics Department is pleased to welcome Professor Gregg Harry, American University for his talk titled, “Internal Friction: The history of LIGOs thermal noise research”.

Bio: Gregory Harry is a physics professor at American University in Washington DC who has been studying optical coatings for gravitational wave detectors for over 20 years.  He received his BS in physics from the California Institute of Technology and PhD in gravitational wave detection from the University of Maryland, College Park.  He did postdoctoral research on the Laser Interferometery Gravitational-wave Observatories (LIGO) at Syracuse University and at the Massachusetts Institute of Technology (MIT).  As a research scientist with the LIGO Laboratory at MIT he served as the Coating Cognizant Scientist for the Advanced LIGO project that built the currently operating gravitational wave detectors in the US.  These detectors made the first detection of gravitational waves, from two colliding black holes, in 2015.  While at MIT and American he conceived and edited the book “Optical Coatings and Thermal Noise in Precision Measurement” in 2012, which characterizes the state of coating research for precision optical measurement, including but not limited to gravitational wave detectors.  Since 2015 he has spearheaded the effort to develop substrate-transferred compound semiconductor Bragg mirrors, specifically epitaxial gallium arsenide/aluminum gallium arsenide multilayers (AlGaAs), for use in ground-based gravitational wave detectors.  This work has been supported by the US National Science Foundation, including a CAREER grant in 2015.

Abstract: Critical to the success of LIGO has been the ability to understand and continually reduce thermal noise, which along with quantum noise, dominates the center of LIGO’s sensitivity curve.  We could not observe black holes if we did not first figure out how to make quiet mirrors. Prof. Harry and Syracuse University were central in that effort.  Gregg led the effort to make the first measurements of  coating thermal noise in Initial LIGO.  He was key to isolating the noise source and developing the current Advanced LIGO coatings, that have now made hundreds of detections.  He will address the current challenges in thermal noise research and his effort to build the next generation of mirrors that are 10x quieter.