The response of laser interferometers to a gravitational wave

摘要

Laser interferometer detectors are widely used in the extensive effort to detect gravitational waves. The interaction of a gravitational wave with light in the interferometer is usually explained in terms of the motion of the "free" mirrors that form the interferometer arms. It is instructive to show that the same result can be obtained by calculating the propagation of an electromagnetic plane wave between free mirrors in the curved space-time induced by the gravitational wave. We find that the plane wave acquires frequency modulation sidebands at the frequency of the gravitational wave. Such sidebands are equivalent to the time-dependent phase shift imposed on the plane wave, as obtained in the conventional calculation.