Estimate of diffraction from Gaussian Beam in Li-Baker HFGW detector

A New Theoretical Technique for the Measurement of High-Frequency Relic Gravitational Waves

“…The background noise discussed in [35,39] did not consider the scattering or diffraction of the strong GB. However it will be shown that classical analyses of such scattering and diffraction [53][54][55][56][57] indicates that their effect will be negligible at the sensitive microwave receivers. In the Li-Baker detector the HFRGW signal manifests itself as detection photons (PPF) created by the interaction of a microwave beam (GB) and the GWs.…”

“…In spite of this, there will be some microwave diffraction photon noise that will need to be reduced before reaching the receivers. Since there is no direct path perpendicular to the GB to the microwave receivers in the x direction or from the edges of the reflectors, due to the Herschelian optical telescope design, all x-directed photons (moving perpendicular to the axis of the GB as computed in [57]) and all diffracted photons from the reflector edge will necessarily encounter a wall of the detection chamber before reaching the receivers. The number of diffraction photons emanating radially from the GB, including the effect of polarization alignment, is given by Equation (13) of [57] where diffraction has been analyzed specifically for the Li-Baker detector.…”

“…The reader is encouraged to review this important analysis since GB diffraction might be considered to be a major source of noise. The diffraction photons per second from the GB is Figure 4 of [57]. We will assume a single bounce or wave reflection of this diffraction-noise wave from the detector walls.…”