Selecting the Best Coatings to Precisely Measure Thermo-Optic Coefficients

Document #:

LIGO-G1501025-v1

Document type:

G - Presentations (eg Graphics)

Abstract:

One possible source of noise in interferometric experiments such as LIGO is thermo-optic noise which is caused by variations in the local temperature of the mirror coatings. To fully characterize this noise source we need to know α (the coefficient of expansion), and β (the change in index of refraction with temperature, dn/dT) for all materials used in the coatings. We are setting up an experiment at Whitman College to measure these coefficients, but we would like to determine which coatings will give us the lowest fractional error on each parameter. We wrote code in Mathematica to analyze sets of coatings, and determine the set that will give us the smallest errors on α and β. After running seventy initial coatings we found a number of good options

Files in Document:

• Ogin_Summer_Research.pdf (896.6 kB)

Topics:

• Basic R&D
• Core Optics

Authors:

• Greg Ogin
• Avery Miller
• Isaac Berez
• Matthew Gabel

Keywords:

Thermo-optic coating CTE alpha beta measurement