1. Harald Lück, AEI Hannover 1 GWADW- May, 10-15, 2009 EU contract #211743

2. ´06´07´08´09´10´11´12´13´14´15´16´17´18´19´20´21´22 Virgo GEO LIGO LISA E.T. Virgo+ E-LIGO Advanced Virgo GEO HF Advanced LIGO DSPCP Construction Comm. Hanford Livingston Launch Transfer data data You are here 1st Generation2nd Generation 3rd Gen. GW Timelines Site Prep.

3.  Interferometer size  As big a finances allow? How big is that?  Over-ground vs under-ground (J. Harms, Jo Van der Brand, D. Rabeling)  Will low frequency performance goals really require underground operation ?  Low frequency suspensions (R. Nawrodt)  Newtonian Noise  Cryogenic operation ( W. Johnson, K. Kuroda )  Is cryogenics really needed to achieve the goals or is room temperature sufficient (at least for high frequencies) ?  Non gaussian beams (A. Freise)  QND tricks (H. Müller-Ebhardt)  Xylophone: collocated multi-narrowband vs single- broadband detector (S. Hild, R. DeSalvo) GWADW - May, 10-15, 2009 3

4.  Substrate material: Silicon  Gratings & wave-guide coatings (H. Lück)  Quantum noise:  Squeezing (A. Khalaidovski)  Laser (N. Man) GWADW - May, 10-15, 2009 4

5. 5 Nawrodt et al.

6. GWADW - May, 10-15, 2009 6 Vanishing CTE @ 20k & 125K Low thermal lensing @ low temp. Fused silica 2E-5 / K @ 300 K No thermoelastic noise Temperature [K] Dn/dT

7. Thermal conductivity Silicon Specific heat Silicon GWADW- May, 10-15, 2009 7

8. Thermal conductivity fused Silica Specific heat Silicon / fused silica GWADW- May, 10-15, 2009 8 1/10 1E4

9. GWADW - May, 10-15, 2009 9 from M. Green and M. Keevers, Optical properties of intrinsic Silicon @ 300K, Progress in Photovoltaic research and Applications, Vol. 3, 189-192 (1995) Wikipedia.com Max. Diameter currently 450mm

10. GWADW - May, 10-15, 2009 10

11.  Refractive index of Silicon @ 1550nm ~ 3.48 @ 300K  Refractive Index of SiO 2 ~ 1.44  fewer layers needed due to difference in refractive indeces GWADW - May, 10-15, 2009 11 Si SiO 2 Si Coating SiO 2 Si Substrate

12. GWADW - May, 10-15, 2009 12 SiO 2 Coating SiO 2 Si SiO Si SiO Substrate High absorption of SiO might be a problem for SiO 2 coatings on Silicon substrates

13. 13 substrate Monolithic 100% reflection “coating” [Brückner et al., Opt. Lett., 33, 264 (2008) ]

14. 14 R > 99.8%, private communication, IAP Jena, R. Schnabel

15. 15 cryst. quartz,  3“  12 mm, 11670 Hz Mechanical losses of gratings Nawrodt et al., New Journal of Physics 9 (2007) 225

16. 16 Extracted coating/grating losses Nawrodt et al., New Journal of Physics 9 (2007) 225

17. GWADW - May, 10-15, 2009 17

18. GWADW - May, 10-15, 2009 18 1064 nm Vahlbruch et al. PRL 100, 033602 (2008)

19. GWADW - May, 10-15, 2009 19 Chelkowski et al., PRA 75, 043814 (2007) 1064 nm Shot noise Squeezed noise electronic darknoise

20. GWADW - May, 10-15, 2009 20 1550 nm Mehmet et. al.: arXiv:0902.0670v1 [quant-ph]

21. GWADW - May, 10-15, 2009 21

22.  Solid state laser:  laser diode pumped solid state laser (AdvLIGO):  210W Nd:YAG, less than 12% in higher order modes, almost finished design for reliable long-term operation  3 E-9 /sqrt(Hz) power stability @ 10Hz, rf noise: 1dB above SN of 100mA @ 9 MHz  fibre laser:  ytterbium doped photonic crystal fiber amplifier using a single- frequency Nd:YAG non-planar ring oscillator seed source  148W, less than 8% in higher order modes  13 November 2006 / Vol. 14, No. 23 / OPTICS EXPRESS 11071 GWADW - May, 10-15, 2009 22

23.  Solid state laser:  -  fibre laser:  Erbium fibre laser, ~2 W, poor reliability GWADW - May, 10-15, 2009 23

24.  1064 nm:  Reach 1kW within next 5 years  RIN < 1 E-9 / √ Hz  1550 nm:  150 W within next few years GWADW - May, 10-15, 2009 24

25. 2022

26. GWADW- May, 10-15, 2009 26

27. GWADW- May, 10-15, 2009 27 http://www.sciner.com/Opticsland/FS.htm Wavelength, µm 0.20.220.250.30.320.360.40.450.5 Refractive Index 1.550511.528451.507451.487791.482741.475291.470121.465571.46233 Wavelength, µm 0.550.590.600.650.70.750.80.850.9 Refractive Index 1.460081.458461.458041.456531.455291.454241.453321.45251.45175 Wavelength, µm 1.01.11.21.31.51.61.71.81.9 2.0 Refractive Index 1.450421.44921.448051.446921.444621.443421.442171.440871.43951 1.43809

28. S. Hild et al, http://arxiv.org/abs/0810.0604 GWADW- May, 10-15, 2009 28