The generation of High‐Frequency Gravitational Waves (HFGW) has been identified as the required breakthrough that will lead to new forms of space propulsion. Many techniques have been devised to generate HFGW, but most of them exhibit marginal efficiency, therefore the power emitted in form of gravitational waves (GW) is orders of magnitude lower than the input power. The gravitational wave counterpart of the LASER, termed Gravitational‐wave LASER or “GASER” is the quantum approach to the efficient generation of gravitational waves. Electrons, protons, muons, etc, all have charge and mass, if accelerated they usually lose energy through the very fast electric and magnetic channels, this causes a negligible emission through the gravitational channel. Quantum systems can be engineered to forbid electric and magnetic transitions, therefore the gravitational spin‐2 transitions can take place. A class of active materials, suitable for making a GASER based on electronic transitions in the solid state, is identified along with their relevant physical properties. Means for creating coherence and population inversion and means to increase the emission probability are described. The expected performances of the device are derived from quantum gravitational theories. Additional properties of the active materials are considered to enforce the theoretical foundation of the device. A proof‐of‐concept device, operating at about 1 THz, is described. Experiments are proposed as a natural starting point of the research. © 2004 American Institute of Physics