Abstract: An example system for detecting pipe defects is provided. The system includes a transmitter, a receiver and a processing device. The transmitter is oriented to transmit Terahertz (THz) waveform pulses towards at least one of an outer surface of a pipe or an inner surface of the pipe. The receiver is oriented to receive reflected Terahertz (THz) waveform pulses from at least one of the outer surface of the pipe or the inner surface of the pipe. The processing device configured is to receive as input the Terahertz (THz) waveform pulses transmitted from the transmitter and the reflected Terahertz (THz) waveform pulses received by the receiver and, based on the received input, determine if a defect in the pipe exists.

Abstract: An example system for detecting pipe defects is provided. The system includes a transmitter, a receiver and a processing device. The transmitter is oriented to transmit Terahertz (THz) waveform pulses towards at least one of an outer surface of a pipe or an inner surface of the pipe. The receiver is oriented to receive reflected Terahertz (THz) waveform pulses from at least one of the outer surface of the pipe or the inner surface of the pipe. The processing device configured is to receive as input the Terahertz (THz) waveform pulses transmitted from the transmitter and the reflected Terahertz (THz) waveform pulses received by the receiver and, based on the received input, determine if a defect in the pipe exists.

Abstract: Non-invasive THz spectroscopic apparatus and methods are provided for measuring the average diffusion coefficients for a structure such as cork. The methods may be used to image the localized presence of water in the structure to produce time-dependent images of liquid propagation in the structure.

Abstract: A method of reducing boundary effect in a THz-CT image includes correcting steering of the THz beam and/or Fresnel reflection prior to reconstruction of the THz image, the method including tomographically scanning an object at selected rotational positions to obtain a plurality of projection slices, and prior to reconstructing the THz-CT image using a Radon transformation, applying to each of the plurality of projection slices an algorithm to determine a location of left and right edges of the object relative to the center of rotation of the object, determining a range of values for which the measured attenuation is not instrument limited based on a maximum detectable attenuation, and applying a further algorithm representing the corrected attenuation projection array data which will be inverted using the Radon transformation, the algorithm including an experimentally measured attenuation, correction for beam steering, and accounting for Fresnel reflection loss at the incident and exiting air-object interface

Abstract: Non-invasive THz spectroscopic apparatus and methods are provided for measuring the average diffusion coefficients for a structure such as cork. The methods may be used to image the localized presence of water in the structure to produce time-dependent images of liquid propagation in the structure.

Abstract: Non-invasive THz spectroscopic apparatus and methods are provided for detecting and/or identifying constituents such as variations in a structural entity where chemical or biological entities can reside. Position dependent scattering of THz radiation is employed to image voids and defects in the internal structure of samples, enabling the determination of contamination, spoilage or readiness of products such as wine in sealed containers.

Abstract: Non-invasive THz spectroscopic apparatus and methods are provided for detecting and/or identifying constituents such as variations in a structural entity where chemical or biological entities can reside. Position dependent scattering of THz radiation is employed to image voids and defects in the internal structure of samples, enabling the determination of contamination, spoilage or readiness of products such as wine in sealed containers.

Abstract: Near field imaging using a THz imaging system is realized by utilizing an interferometric imaging detector array that includes detector elements disposed on a surface curved, physically or artificially, to match substantially the curvature of the wave front for received THz signals. Generally, the near field is an environment wherein the distance to an object of interest is on the order of 10–100 times larger than the physical size of the THz imaging array. Typical distances from the object or target to the imaging array is anticipated to be in the 0.5 m–50 m range. Curvature of the detector array corrects a distortion problem in prior THz imaging systems that utilized planar interferometric imaging arrays based on a planar wave front assumption for received THz signals.

Abstract: A two-stage optical fiber amplifier requiring substantially reduced power comprises a pre-amplifier first-stage operating in the linear region within the small signal limits, and a post-amplifier second-stage operating in a saturated regime providing significant gain compression. The pump power for the pre-amp stage is minimized, and all of the gain compression occurs in the second stage. Minimum pump power and the corresponding amplifier fiber length needed to achieve a predetermined optimum amount of small signal gain required in a given amplifier application may be achieved in variations of the design.