HOW AN INTERFEROMETER EXTRACTS AND AMPLIFIES POWER FROM A GRAVITATIONAL-WAVE

The operation of an interferometric gravitational wave detector is des cribed in terms of the power flow through the device. I show how to id entify the mechanical power absorbed by the interferometer from the gr avitational wave and describe the power gain provided by the interfero meter using the classical theory of parametric transducers. I discuss the power relationships involved in the optical heterodyne process at the output photodiode. I compare various possible definitions of the c ross section of an interferometer with the definition used in the desc ription of a resonant-mass gravitational wave detector.