Terahertz (THz) radiation occupies a large portion of the electromagnetic spectrum between the infrared and microwave bands and is a developing frontier in imaging science and technology. In contrast to the relatively well-developed techniques for imaging at microwave and optical frequencies, however, there has been only limited basic research, new initiatives, and advanced technology developments in the THz band.

The photonic and optoelectronic communities have long been interested in the development of tunable delay systems for optical pulses. The various systems developed suffer from shortcomings such as limited delay range for high speed devices, low duty cycles and nonlinearity in optical path-length change, the inability to provide tens of centimeter scanning range and a repetition rate in the hundreds of hertz range, and low temporal resolution and optical loss.

Terahertz (THz) waves occupy a segment of the electromagnetic spectrum between the infrared and microwave bands. As such, they can be used for imaging and sensing in ways not possible with conventional technologies such as X-ray and microwave. Because THz radiation transmits through almost anything that is not metal or liquid, the waves can see through most materials that might be used to conceal explosives or other materials, such as packaging, corrugated cardboard, clothing, shoes, backpacks, and book bags.

This invention is directed to a system and method to create three dimensional tomography using a Fresnel lens with broadband terahertz (THz) pulses.The procedure allows reconstruction of an objects tomographic contrast image by assembling the frequency-dependent images.Objects at various locations along the beam propagation path are uniquely imaged on the same imaging plane using a Fresnel lens with different frequencies of the imaging beam.

This invention is directed to techniques for obtaining and imaging three-dimensional objects using radiation in the terahertz (THz) spectrum and systems and associated methods for high resolution terahertz computed tomography. Although computed tomography is well known in X-ray radiographic imaging, a serious problem in reconstructing an image using THz computed tomography is that the THz wave does not satisfy the short wave limit as the X-ray satisfies in X-ray computed tomography.

Terahertz (THz) waves occupy a segment of the electromagnetic spectrum between the infrared and microwave bands. As such, they can be used for imaging and sensing in ways that are not possible with conventional technologies such as X-ray and microwave. Because THz radiation transmits through almost anything that is not metal or liquid, the waves can see through most materials that might be used to conceal explosives or other materials, such as packaging, corrugated cardboard, clothing, shoes, backpacks, and book bags. They are also safer than X-rays and microwaves for human tissue.

Electro-optic crystals and photoconductive dipole antennas have been widely used in terahertz (THz) time-domain spectroscopy and related imaging applications. In the standard apparatus used for THz time-domain spectroscopy a separate transmitter and receiver are used for the emission and detection of the THz signal. Because detection is the reverse process of emission, the transmitter and the receiver can be identical devices.

Recently, Terahertz time domain spectroscopy (THz-TDS) has emerged as a successful method to measure the refractive index of thin solid films without sample perturbation. However, a need remains for a new non-invasive biosensor technology having application, for example, in healthcare, food monitoring, and weapon detection. This invention is directed to a method for detecting specific associations between a tethered molecule and an untethered target molecule, thus providing a method of probing bimolecular interactions using THz radiation.