Terahertz investigation of X-ray anti-imaging coatings: Spectroscopic characterization and imaging

An investigation of the terahertz properties of x-ray blocking and scattering (XBS) coating materials is performed. Spectral characterizations of the XBS materials reveal much stronger absorption coefficients as compared to the control coatings, as well as significant change in the refractive index. To examine the effectiveness of the coating material, pulsed THz reflection images of coated electronic microchip circuits are obtained. The microchips are covered with XBS coatings of varying thickness. The results demonstrate that this coating can successfully block the incident THz signal between 0.08 and 4 THz if the coating is sufficiently thick. This allowed for the proper thickness of the coating to be determined such that potential intellectual property contained in the microchip design could be protected from THz imaging.