Trade-off between quantum and thermal fluctuations in mirror coatings yields improved sensitivity of gravitational-wave interferometers

摘要

We propose a simple way to improve the laser gravitational-wave detectorssensitivity by means of reduction of the number of reflective coating layers ofthe core optics mirrors. This effects in the proportional decrease of thecoating thermal noise, the most notorious among the interferometers technicalnoise sources. The price for this is the increased quantum noise, as well ashigh requirements for the pump laser power and power at the beamsplitter.However, as far as these processes depend differently on the coating thickness,we demonstrate that a certain trade-off is possible, yielding a 20-30% gain(for diverse gravitational wave signal types and interferometerconfigurations), providing that feasible values of laser power and power on thebeamsplitter are assumed.