Hannover 2016 – scientific programme

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A: Fachverband Atomphysik

A 1: Precision Measurements and Metrology I (with Q)

A 1.5: Talk

Monday, February 29, 2016, 12:00–12:15, a310

Coating Thermal Noise Interferometer — •Janis Wöhler for the AEI 10m Prototype Team — MPG for Gravitational Physics Hannover

Thermal noise in the coatings of highly reflective mirrors is becoming a limiting noise source in interferometers used for the detection of gravitational waves. It is caused by mechanical losses of the thin films used in the coatings. A way to reduce the noise is to use crystalline coatings due to their inherently lower mechanical losses. Crystalline AlGaAs-coatings are a promising candidate and their noise properties will be measured before using them in a quantum limited Michelson interferometer. For the measurement, all other noise sources, especially seismic noise and acoustic disturbances, have to be reduced below the thermal noise level. The AEI 10 m Prototype facility is probably the best suited environment for this kind of experiment.

In this talk the setup of the Thermal Noise Interferometer will be presented, which can measure thermal noise in a frequency band from 10Hz to 50kHz, limited from below by seismic noise and from above by photon shot noise. Furthermore prospects of using crystalline coatings in large scale gravitational wave detectors will be discussed.