1. Work Package 4: Development of low loss dielectric coatings for advanced detectors Scientific motivation: Mechanical dissipation from dielectric mirror coatings is predicted to be a significant source of thermal noise for advanced detectors. Coatings must also be of low optical loss. - Main workpackage outcomes/long term aim: Definition of a low-mechanical-loss optical coating design/production process suitable for advanced detectors operating at either room or cryogenic temperatures - Groups involved: Institute for Gravitational Research, University of Glasgow Laboratoire des Matériaux Avancés, (LMA) Lyons AURIGA group, Laboratori Natzionali di Legnaro (+Leiden/Rome) Materials group, VIRGO, Perugia ESPCI, Laboratoire d'Optique, Paris

2. Work Package 4: Development of low loss dielectric coatings for advanced detectors Milestones Year 1Report from Glasgow Group (IGR) 4.1 - Production of the first SiO 2 /Ta 2 O 5 and SiO 2 /Al 2 O 3 coatings Status: Coatings procured from REO and Waveprecision. Deliverables Year 1 4.2 - Loss measurements on SiO 2 /Ta 2 O 5 at room T Status: Given the availability of results from work by the LIGO project on SiO 2 /Ta 2 O 5 we chose to pursue studies of Al 2 O 3 /Ta 2 O 5 coatings (relevant for use with sapphire mirror substrates) We have previous experimental measurements which we are re- analysing in greater depth for this project given our new work on FEA and improved interpretation of sources of coating dissipation. This work is continuing as planned. 4.3 - Loss measurements on SiO 2 /Al 2 O 3 at room T Status: A SiO 2 /Al 2 O 3 coating on sapphire has been procured – we plan to carry out measurements of the coating mechanical loss. This work is continuing as planned.

3. Facility to measure the Q of coated membranes realized under the EGO R&D program and delivered to Lyon Report from INFN Perugia

4. The Michelson Morley InterferometerData analysis program Preliminary measurements in Perugia for clamping design

5. Work Package 4: Development of low loss dielectric coatings for advanced detectors Milestones of STREGA proposal for next year: Milestone Year 2production of first SiO 2 /high index material Deliverables Year 2measurements on silica substrate identification of diffraction coating production process Scientific plan for next year: Some EGO funding is approved for coating research - LMA Lyons We propose –Substrates to be provided by collaborating STREGA institutions –Thin ‘membranes’ to be used initially for fast test measurements (INFN Perugia)

6. Work Package 4: Development of low loss dielectric coatings for advanced detectors Scientific plan for next year, cont. - Smaller number of larger ‘mirror-like’ samples for further study in more realistic configurations INFN Perugia, Glasgow (participation by Legnaro/Leiden/Rome) - Move over coming year to study coatings on some silicon substrates (for use at 1064nm initially) - Choice of specific coatings – doping etc – subject of near future discussion – propose WP4 meeting in Lyons Costs an issue..