Optomechanical issues in the gravitational wave detector Advanced VIRGO

The next generation of the gravitational wave detector VIRGO, namely Advanced VIRGO, will feel an enhancement of optomechanical effects. In fact, it is planned that cavities will be antisymmetrically detuned to compensate symmetry defects between the two arms, which then allows DC detection. In this article, we show that even with slight detuning, the high intra-cavity power stored within the Fabry–Perot cavities makes optical spring effects important enough to constrain the detector adjustment procedure and to limit its sensitivity.