An interaction between gravitational and electromagnetic waves

A rotation of the plane of polarization of an electromagnetic wave results from the passage of the wave through a region with non-zero curvature tensor, as occurs when a gravitational wave is present. Although this effect is small when integrated over distances comparable to the wavelength of gravitational waves, there are plausible geometrical situations in which the effect is cumulative over long path lengths. In addition the interaction can take place close to the source of gravitational waves where the dimensionless wave amplitude can be large. The magnitude of the expected rotation is estimated for a few astronomical sources of gravitational waves.