Thermal noise study of a radiation pressure noise limited optical cavity with fused silica mirror suspensions

In this work we study the thermal noise of two monolithically suspended mirrors in a tabletop high-finesse optical cavity. We show that, given suitable seismic filters, such a cavity can be designed to be sensitive to quantum radiation pressure fluctuations in the audio band of gravitational wave interferometric detectors below 1 kHz. Indeed, the thermal noise of the suspensions and of the coatings constitutes the main limit to the observation of quantum radiation pressure fluctuations. This limit can be overcome with an adequate choice of mirror suspension and coating parameters. Finally, we propose to combine two optical cavities, like those modeled in this work, to obtain a tabletop quantum radiation pressure-limited interferometer.