Surveillance Applications of High-Frequency Gravitational Waves

This paper explores the possibility of utilizing a novel means of imaging to establish a system of surveillance - a system that may allow for the observation in three-dimensions of activities within and below structures and within the Earth and its oceans. High-Frequency Gravitational Waves (HFGWs) pass through most material with little or no attenuation; but although they are not absorbed their polarization, phase velocity (causing refraction or bending of GWs) and/or other characteristics can be modified by a material object's texture and internal structure. For example, the change in polarization of a GW passing through a material object is discussed in Misner, Thorne, and Wheeler (1973). Specifically, 'If the wave is a pulse, then the backscatter will cause its shape and polarization to keep changing ' Such an assertion will need to be verified both theoretically and experimentally, but the potential payoffs are enormous. Applications of this technology include satellite-based surveillance systems to image subterranean weapons of mass destruction or WMDs, personnel of interest inside and behind buildings, deeply submerged submarines, hidden missiles and rockets, oil and mineral deposits, etc. as well as acoustical surveillance. The Laser Interferometer Gravitational Observatory or LIGO and other interferometer detectors cannot detect HFGWs due to the HFGW's short wavelengths as discussed by Shawhan (2004). Long-wavelength gravitational waves having thousand and million meter wavelengths, which can be detected by LIGO, are of no practical surveillance value due to their diffraction and resulting poor resolution. Short HFGW wavelengths of a few meters to fractions of a millimeter and the sensitivity of the HFGW generator-detector system to polarization angle changes of yoctoradians to 10-40 radians could afford suitable resolution for practical surveillance systems.