Exploitation of variable phase-shifter for very-high-frequency gravitational waves

Woods recently described how a type-II superconductor acts as a phase-shifter for gravitational waves (GWs). The precise phase-shift is determined by an applied magnetic field. Therefore, using a suitable non-uniform magnetic field, the GW path length may be arranged to vary in a technologically useful manner. The present paper shows how this result may be exploited, by describing the design of a novel type of lens for very-high-frequency GWs, using a magnetic field to adjust the focal length in an infinitely variable manner. Such a lens would be invaluable in the design of advanced GW optics. The device would also enable fast auto-focusing, zooming, and imaging tomography using electronic servos following development of the necessary GW detectors.