BS and Mirrors for the LCGT Norikatsu Mio, PSC Univ. of Tokyo Eiichi Hirose, ICRR Univ. of Tokyo December 13, 2011 CSIRO, Lindfield Australia

LCGT 2011/12/13CSIRO, Lindfield AUSTRALIA Underground Low seismic noise Cryogenic mirrors and suspensions Reduction of thermal noise Tokyo Gifu SEM ITMX ETMX ITMY ETMY BS PRM MC 1 st stage: Room-temp. Operation → Silica TM (ITM and ETM) 2 nd stage: Cryogenic Operation → Sapphire TM Laser We would like to discuss possibility that CSIRO fabricates BS and possibly silica TMs 2

Overview of LCGT mirrors iLCGT – Room temperature – Silica mirrors – Modest laser power(<10W?) – Limited time for construction bLCGT – Cryogenic system – Sapphire mirrors – High power laser – Recycling system 2011/12/13CSIRO, Lindfield AUSTRALIA3

Laser MC1 MC2 MC3 PRMPR1 PR2 BS SR2 SR1 SRM ITMX ITMY ETMX ETMY MT1 MT2  25cm  38cm  10cm Mirrors for Main cavities Initial: Silica Final: Sapphire Core optics of LCGT 2011/12/13CSIRO, Lindfield AUSTRALIA4

Requirement s for iLCGT mirrors iLCGT – Room temperature – Silica mirrors – Modest laser power(<10W?) – Limited time for construction – Size of the mirrors for the main interferometer – 25cm in diameter 10cm in thickness – Most of them will be made from iLIGO mirrors 52011/12/13CSIRO, Lindfield AUSTRALIA

Current Plan For iLCGT, the size of the mirrors is chosen as that of iLIGO’s mirror. BS and ITMs will be newly fabricated from Japanese Silica. We have obtained some of the iLIGO mirrors. 2011/12/13CSIRO, Lindfield AUSTRALIA6

Beam Splitter 2011/12/13CSIRO, Lindfield AUSTRALIA SubstrateSilicaAGC(Asahi Glass Corporation), AQ2 Diameter38cm Thickness8cm Wedge (S2 side) 0.383° （ ±0.008° ） Incident angle 45.15° （ ±0.05° ） 1064nm50%(±1%) 532nm> 0.9 S1S-state Beam Splitter ROCFlat (> 100km)as flat as possible Astigmatism Z228nm r < 100mm2nm r < 170mm3nm HSF (Micro Roughness, >1mm-1)0.3nm 1064nm< 100ppm 532nm< 1% S2AR ROCFlat (> 100km)as flat as possible r < 100mm2nm r < 170mm4nm HSF (Micro Roughness, >1mm-1)0.5nm 1064nm< 50ppm 532nm< 5% 7

ITM 2011/12/13CSIRO, Lindfield AUSTRALIA SubstrateSilicaAGC(Asahi Glass Corporation), AQ2 Diameter25cm Thickness10cm Wedge (S2 side) 0.2° （ ±0.002° ） 1064nm0.004(+0.001/-0) 532nm0.2(±0.1)Transission of ITM must be larger than 532nm Transmission 1064nm< 0.012*|(T1-T2)/(T1+T2)| where T1, T2 are transmission of ITMX, ITMY Transmission 532nmNo requirement S1HR ROC 1.68km （ ±0.008km ） 0.5% error Astigmatism Z223nm r < 70mm0.5nm LSF( 70mm2nm HSF (Micro Roughness, >1mm-1)0.16nm 1064nm< 45ppm 532nm< 1% S2AR ROCFlat (> 100km)as flat as possible r < 70mm2nm LSF( 70mm4nm HSF (Micro Roughness, >1mm-1)0.5nm 1064nm200ppm (+100/-0ppm) 532nm< 5%as small as possible 8

ETM 2011/12/13CSIRO, Lindfield AUSTRALIA SubstrateSilicaETMs used in initial LIGO Diameter25cm Thickness10cm Wedge (S2 side) 0.2° （ ±0.002° ） 1064nm5ppm < T < 10ppm 532nm0.2(±0.1)Transission of ITM must be larger than 532nm Transmission 1064nm< 0.01Best effort Transmission 532nmNo requirement S1HR ROC 1.87km （ ±0.009km ） 0.5% error Astigmatism Z223nm r < 70mm0.5nm LSF( 70mm2nm HSF (Micro Roughness, >1mm-1)0.16nm 1064nm< 45ppm 532nm< 1% S2AR ROCFlat (> 100km)as flat as possible entire surface40nm HSF (Micro Roughness, >1mm-1)2nm 1064nm200ppm (+100/-0ppm) 532nm< 5%as small as possble 9

Schedule BS – Delivery: March, 2013 – Contract: February or March, 2012 ? Arm Mirrors – Delivery: March, 2014 (?) – Contract: some day in 2013 (?) or 2012?? Formal budget will be funded by the end of FY2012 (March, 2013); the extension is maybe possible. 2011/12/13CSIRO, Lindfield AUSTRALIA10

Things to be discussed 2011/12/13CSIRO, Lindfield AUSTRALIA Specification (both BS and TMs) Quotation (delivery date, cost etc) Contract (representative in Japan, deposit etc) Any other items 11