  In this paper, we address the question as to whether or not measurable
sources for gravitational waves could possibly be made in the laboratory. Based
on an analogy of the dynamical Casimir effect with the stimulated emission of
radiation in the laser, our answer to this question is in the affirmative,
provided that superconducting radio-frequency cavities in fact possess high
quality factors for both electromagnetic and gravitational microwave radiation,
as one would expect due to a quantum-mechanical gravitational Meissner-like
effect. In order to characterize the response of matter to tensor gravitational
fields, we introduce a prefactor to the source term of the gravitational wave
equation, which we call the "relative gravitational permeativity" analogous to
the "relative electric permittivity" and "relative magnetic permeability" that
characterize the vector response of matter to applied fields in
electromagnetism. This allows for a possibly large quantum mechanical
enhancement of the response of a superconductor to an incident tensor
gravitational wave field. Finally, we describe our experimental work with
high-Q superconducting radio-frequency cavities, and propose a design for a
coupled-cavity system with a flexible superconducting membrane in its middle as
its amplifying element. This will then allow us to test for a Meissner-like
expulsion, and therefore reflection, of incident tensor gravitational wave
fields, and, above a certain threshold, to generate coherent gravitational
radiation via the dynamical Casimir effect.
