Dedicated to Robert Kirk Burrows

In 1999, I was a young postdoc moving to Syracuse University to work on LIGO, which had been a dream of mine since I was first introduced to gravitational wave detection as an undergraduate in Kip Thorne's class at Caltech. I had done my PhD in gravitational wave detection, but using the older technology of resonant masses rather than LIGO's laser inteferometry. I was concerned that my background would not prove appropriate. I soon found a common issue, thermal noise, that I was able to focus on. Beyond just a good fit for me, thermal noise was actually a topic in flux within LIGO at the time. A talented young theorist at Caltech named Yuri Levin had just shown that the optical coatings on the LIGO mirrors could well contribute much more thermal noise than anyone had anticipated. What was missing were realistic numbers to plug into Yuri's formulas to see just how big of an impact coating thermal noise might have. This became one of my principal roles in LIGO, as part of a group of experimentalists interested in this question at Stanford, Glasgow, as well as Syracuse and other collaborating institutions.

Since then, we in LIGO have found that coating thermal noise is a very important limit to sensitivity, and we have engaged in over a decade of theoretical, experimental, and modeling work to better understand and reduce it.