1. LIGO-G030154-00-Z 1 Report of the Optics Working Group to the LSC David Reitze University of Florida March 20, 2003

2. LIGO-G030154-00-Z 2 Summary Lots of Progress »Sapphire properties and limitations »Fused silica Q »Coatings properties and optimization »New ideas Lots of Challenges »Thermal noise in coatings of concern »Sapphire hitting an absorption wall »Absorption Inhomogeneities? Lots of Work to Do »AdLIGO test mass material downselect approaching (July-August) »Coatings, coatings, coatings…

3. LIGO-G030154-00-Z 3 Sapphire mechanical properties Q Q measurement by Phil Willems »Two 314 mm x 130 mm boules measured »Highest Q ~ 260x10 6 radial antisymmetric mode »Lowest Q ~ 28x10 6 Similar for “good” and “not” substrates »Slightly better for “not!” Willems/Billingsley

4. LIGO-G030154-00-Z 4 Position (arb.) Absorption (ppm/cm) Sequential z-scans of 23-1-B heated to 1200º C in N2 and cooled at rates shown Increasing surface degradation from oxygen impurity in N 2 #1 - 20 C/hr #2 - 55 C/hr #3 - 100 C/hr #4 - 200 C/hr #5 - 400 C/hr #6 - 800 C/hr Route

5. LIGO-G030154-00-Z 5 ACIGA Gingin Facility Zhao

6. LIGO-G030154-00-Z 6 MEXICAN-HAT [MH] BEAM (a near optimal type of flat-topped beam) MH beam shape: »Superposition of minimal-spreading Gaussians -- axes uniformly distributed inside a circle of radius D »Choose D so diffraction losses are 10 ppm D MH mirror shape: matches phase fronts of MH beam Spherical, Rcurv = 78 km Mexican Hat Thorne

7. LIGO-G030154-00-Z 7 BNS Range Y coat = 70 GPa BNS Range Y coat = 200 GPa Coating  Material downselect Coating loss Harry

8. LIGO-G030154-00-Z 8 Coating thermoelastic noise: Al 2 O 3 /Ta 2 O 5 on sapphire substrate Advanced LIGO displacement noise requirement for each test mass at 100Hz x(f) in m/  Hz Fejer and Rowan

9. LIGO-G030154-00-Z 9 TNI Sensitivity after Second Round of Improvements Black

10. LIGO-G030154-00-Z 10 Lots of Progress Lots of Challenges Lots of Work to Do… Conclusions