Orthorhombic Cuprate High Temperature Superconductors (HTSC) are characterized by the
presence of both s-wave and d-wave Cooper pairs in their electronic structure, and it is known from theory
that electronic transitions between s and d states may produce the emission of gravitational waves. In normal
materials, s-d transitions are suppressed by competing electric and magnetic transitions that have much higher
probabilities; this is not the case of Cooper pairs in HTSC, which cannot support states other than s-wave or dwave.
To give theoretical foundations to a potential technology capable of constructing a quantum source of
gravitational waves, this paper will also discuss means for creating coherence and population inversion and
means to increase the emission probability, with close resemblance to the conceptual developments that led to
the experimentation of the first laser. The expected performances of the device are derived from quantum
gravitational theories. Additional properties of the active materials are considered in order to enforce the
theoretical foundations of the device. A proof-of-concept device, operating at about 1 THz, is described.
Keywords: Gravitational waves, gravitational waves from quantum systems, quantum coherence, laser
emission, theories of gravitation, superconductors, high-Tc superconductors, low-Tc superconductors, swave
and d-wave pairs in superconductors, general relativity, gravity-like fields.
