Abstract: A system for determining at least one property of a sheet dielectric sample using terahertz radiation includes at least one terahertz transmitter configured to output a pulse of terahertz radiation, a terahertz receiver configured to receive at least a portion of the pulse of terahertz radiation, wherein the terahertz receiver is configured to output a measured waveform based on the terahertz radiation received by the terahertz receiver, and a control unit in communication with the terahertz receiver. Wherein the control unit is configured to choose at least one region of interest of the measured waveform, compare the at least one region of interest of the measured waveform to a model waveform, vary at least one parameter of a model waveform to minimize the difference between the model waveform and the measured waveform.

Abstract: A system and method for detecting anomalies concealed upon a person may include a detection probe having an electromagnetic transmitter and an electromagnetic receiver. The electromagnetic transmitter is configured to emit electromagnetic pulses, while the electromagnetic receiver is configured to sample electromagnetic pulses from the electromagnetic receiver at specified times within a waveform window. The electromagnetic pulses may span the terahertz spectral region of 0.04 to 4 THz. The system may also have optical fibers connected to the electromagnetic transmitter and electromagnetic receiver, wherein femtosecond laser pulses are directed from a source to the electromagnetic transmitter and the electromagnetic receiver by the optical fibers.

Abstract: A system for determining a material property at an interface between a first layer and a second layer includes a transmitter outputting electromagnetic radiation to the sample, a receiver receiving electromagnetic radiation that was reflected by or transmitted though the sample, and a data acquisition device. The data acquisition device digitizes the electromagnetic radiation to yield waveform data. The waveform data represents the radiation reflected by or transmitted though the sample. The material property to be determined is generally the adhesive strength between the first and second layers.

Abstract: A system for determining at least one property of a sheet dielectric sample using terahertz radiation includes at least one terahertz transmitter configured to output a pulse of terahertz radiation, a terahertz receiver configured to receive at least a portion of the pulse of terahertz radiation, wherein the terahertz receiver is configured to output a measured waveform based on the tera-hertz radiation received by the terahertz receiver, and a control unit in communication with the terahertz receiver. Wherein the control unit is configured to choose at least one region of interest of the measured waveform, compare the at least one region of interest of the measured waveform to a model waveform, vary at least one parameter of a model waveform to minimize the difference between the model waveform and the measured waveform.

Abstract: A system for interpreting terahertz radiation includes a terahertz transmitter configured to output a pulse of terahertz radiation and a terahertz receiver configured to receive at least a portion of the pulse of radiation from the terahertz transmitter. The terahertz receiver is configured to output a signal based on the radiation received by the terahertz receiver.

Abstract: A system for interpreting terahertz radiation includes a terahertz transmitter configured to output a pulse of terahertz radiation and a terahertz receiver configured to receive at least a portion of the pulse of radiation from the terahertz transmitter. The terahertz receiver is configured to output a signal based on the radiation received by the terahertz receiver.

Abstract: A system and method for detecting anomalies concealed upon a person may include a detection probe having an electromagnetic transmitter and an electromagnetic receiver. The electromagnetic transmitter is configured to emit electromagnetic pulses, while the electromagnetic receiver is configured to sample electromagnetic pulses from the electromagnetic receiver at specified times within a waveform window. The electromagnetic pulses may span the terahertz spectral region of 0.04 to 4 THz. The system may also have optical fibers connected to the electromagnetic transmitter and electromagnetic receiver, wherein femtosecond laser pulses are directed from a source to the electromagnetic transmitter and the electromagnetic receiver by the optical fibers.

Abstract: A system and method to measure, with increased precision, the transit time position(s) of pulses in a time domain data. An example data set would be the transit time of pulses in Time-Domain Terahertz (TD-THz) data. The precision of the pulse timing directly affects the precision of determined sample properties measurements (e.g., thickness). Additionally, an internal calibration etalon structure and algorithm method provides for continuous system precision/accuracy check method to increase sample measurement integrity. The etalon structure can improve the precision of sample property measurements (e.g., absolute thickness). Various hardware and system implementations of the above are described.

Abstract: A system for reducing effects relating to stretching of an optical fiber includes an optical control source, the optical source outputting an optical signal, a terahertz transmitter and receiver both being optically coupled to the optical source, and a means for providing the optical signal to both the terahertz transmitter and terahertz receiver such that the terahertz receiver is synchronized to the terahertz transmitter by the optical signal. The means prevents the stretching of an fiber carrying the optical signal provided to the terahertz transmitter or terahertz receiver or allows for the stretching an optical fiber such that the terahertz receiver will still be synchronized to the terahertz transmitter by the optical signal.

Abstract: A system for varying a delay of an optical beam has a rotatable wheel and a set of one or more prisms mounted about a circumference of the rotatable wheel. The set of one or more prisms are positioned to retroreflect the optical beam that passes approximately tangent to the rotatable wheel to cause a delay or phase shift to the beam as the rotatable wheel rotates.

Abstract: A system for determining a material property at an interface between a first layer and a second layer includes a transmitter outputting electromagnetic radiation to the sample, a receiver receiving electromagnetic radiation that was reflected by or transmitted though the sample, and a data acquisition device. The data acquisition device is configured to digitize the electro-magnetic radiation reflected by or transmitted though the sample to yield waveform data, wherein the waveform data represents the radiation reflected by or transmitted though the sample, the waveform data having a first magnitude, a second magnitude and a third magnitude. The material property to be determined is generally the adhesive strength between the first and second layers.

Abstract: A system for reducing effects relating to stretching of an optical fiber includes an optical control source, the optical source outputting an optical signal, a terahertz transmitter and receiver both being optically coupled to the optical source, and a means for providing the optical signal to both the terahertz transmitter and terahertz receiver such that the terahertz receiver is synchronized to the terahertz transmitter by the optical signal. The means prevents the stretching of an fiber carrying the optical signal provided to the terahertz transmitter or terahertz receiver or allows for the stretching an optical fiber such that the terahertz receiver will still be synchronized to the terahertz transmitter by the optical signal.

Abstract: A system and method to measure, with increased precision, the transit time position(s) of pulses in a time domain data. An example data set would be the transit time of pulses in Time-Domain Terahertz (TD-THz) data. The precision of the pulse timing directly affects the precision of determined sample properties measurements (e.g., thickness). Additionally, an internal calibration etalon structure and algorithm method provides for continuous system precision/accuracy check method to increase sample measurement integrity. The etalon structure can improve the precision of sample property measurements (e.g., absolute thickness). Various hardware and system implementations of the above are described.

Abstract: A system for dispersion compensation in a terahertz system includes an optical fiber configured to transmit an optical pulse, a compensator optically coupled to the optical fiber, the compensator configured to compensate for a dispersion of the optical pulse caused as the optical pulse propagates through the optical fiber, and an optically induced terahertz device optically coupled to the compensator, whereby the optically induced terahertz device is configured to transmit or receive terahertz radiation.

Abstract: A system to detect an article includes one or more terahertz modules. Each module either generates or receives, or both generates and receives, terahertz radiation. Some of the terahertz radiation is reflected from the article and the remainder of the terahertz radiation is transmitted through the article. A processor analyzes the reflected and transmitted terahertz radiation to characterize the article.

Abstract: An optical delay line device includes a rotatable wheel and one or more prisms mounted about the circumference of the wheel. The one are more prisms are positioned to retroreflect the optical beam that passes approximately tangent to the wheel to cause a delay or phase shift to the beam as the wheel rotates.

Abstract: A system to detect an article includes one or more terahertz modules. Each module either generates or receives, or both generates and receives, terahertz radiation. Some of the terahertz radiation is reflected from the article and the remainder of the terahertz radiation is transmitted through the article. A processor analyzes the reflected and transmitted terahertz radiation to characterize the article.

Abstract: The present invention includes a semiconductor epitaxial structure optimized for photoconductive free space terahertz generation and detection; and amplifier circuits for photoconductively sampled terahertz detection which may employ the optimized epitaxial structures.

Abstract: An industrially hardened terahertz electromagnetic transmitter and receiver module (29) is disclosed. The electromagnetic wave module has an optic (30) which relays an optical pulse from the delivery fiber (32) to the terahertz device. The relay optic (30) allows for a greatly reduced optical spot size as compared to the output of the optical fiber. Thus, the sensitivity of the overall system is enhanced by improving the efficiency of the terahertz device. The relay optic (30) allows the small spot of light to be aligned to the electromagnetic transmitter or receiver with sub-micron precision.

Abstract: The present invention includes a semiconductor epitaxial structure optimized for photoconductive free space terahertz generation and detection; and amplifier circuits for photoconductively sampled terahertz detection which may employ the optimized epitaxial structures.