Abstract: A system and method for measuring thicknesses of layers of a multi-layered structure. The method includes generating a terahertz wave pulse, transmitting the terahertz wave pulse to a multi-layered structure having multiple layers of materials, receiving reflected terahertz wave pulses reflected by boundaries between the multiple layers as the terahertz wave pulse penetrates the structure, and processing the reflected terahertz wave pulses to: (i) determine whether the reflected terahertz wave pulses have a pulse width overlap; (ii) in response to determining that a pulse width overlap exists, generate modified reflected terahertz wave pulses; measure the time delays associated with each of the modified reflected terahertz pulses and (ii) determine a thickness of each of the multiple layers of materials based upon the time delay and a material refractive index of each of the materials.

Abstract: A terahertz-based material identification system includes a terahertz source for transmitting a terahertz wave for interaction with an object. The interaction results in a resulting terahertz wave that is influenced by the object. A terahertz detector receives the resulting terahertz wave and is configured to output measurement data corresponding to the resulting terahertz wave. A processor is in communication with the terahertz detector for receiving the measurement data. The processor is also configured to calculate an object response signature based on the measurement data, and compare the object response signature to a set of known response signatures so as to identify the object. The material identification system may also be implemented as part of a sorting system that is configured to selectively separate the object from a mixture based on the identity of the object.

Abstract: An apparatus for transmitting or receiving terahertz waves includes an enclosure having a front opening, a rear opening, and an internal passageway therebetween. The enclosure includes an antenna mounting structure and a lens mounting structure. A terahertz photoconductive antenna is mounted within the enclosure against the antenna mounting structure. The terahertz photoconductive antenna has a rear side for being optically energized by an optical beam passing through the rear opening of the enclosure, and a front side for transmitting or receiving the terahertz waves through the front opening. A terahertz lens is mounted within the enclosure against the lens mounting structure. The terahertz lens is positioned between the front opening and the terahertz photoconductive antenna for converging the terahertz waves being transmitted or received. The antenna mounting structure and the lens mounting structure are configured to optically align the terahertz photoconductive antenna and the terahertz lens.

Abstract: A terahertz-based material identification system includes a terahertz source for transmitting a terahertz wave for interaction with an object. The interaction results in a resulting terahertz wave that is influenced by the object. A terahertz detector receives the resulting terahertz wave and is configured to output measurement data corresponding to the resulting terahertz wave. A processor is in communication with the terahertz detector for receiving the measurement data. The processor is also configured to calculate an object response signature based on the measurement data, and compare the object response signature to a set of known response signatures so as to identify the object. The material identification system may also be implemented as part of a sorting system that is configured to selectively separate the object from a mixture based on the identity of the object.