This technology relates to detecting radiation by directing an optical beam into a volume of gas, ionizing a portion of the volume of gas with the optical beam to produce a plasma, and then detecting an acoustic signal produced from an interaction of a radiation wave with the plasma. This technology relates to the phenomenon of enhanced acoustic emission from laser-induced plasma under the influence of a single-cycle terahertz pulse. Aspects of this technology bridge the unintentional gap between THz photonics and photo-acoustics.

This technology relates to a plasma diagnostic method by directing THz radiation into plasma and detecting an emission due to the interaction of the THz radiation with the plasma to characterize the plasma. 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.

This technology relates to detecting terahertz radiation using an optical beam in a volume of gas. Ionizing a portion of the volume of gas with the optical beam produces a plasma and fluorescence is produced from an interaction of a radiation wave with the plasma. Information contained in the characteristics of the detected fluorescence can be used to characterize the radiation wave. Terahertz (THz) waves occupy a segment of the electromagnetic spectrum between the infrared and microwave bands.

Using air as an emitting medium to generate terahertz wave has attracted attention because of its potential applications for remote distance THz wave sensing and imaging. Yet, the cutting edge energy conversion efficiency of THz wave generation with optical method is extremely low. Researchers at Rensselaer have developed a method for generating amplified terahertz radiation that includes inducing a first volume of a gas to produce a seed plasma and emit pulsed seed terahertz radiation by focusing an optical seed beam in the first volume.

Using air as an emitting medium to generate terahertz wave has attracted attention because of its potential applications for remote distance THz wave sensing and imaging. Yet, the cutting edge energy conversion efficiency of THz wave generation with optical method is extremely low. Researchers at Rensselaer have developed a method for generating amplified terahertz radiation that includes inducing a first volume of a gas to produce a seed plasma and emit pulsed seed terahertz radiation by focusing an optical seed beam in the first volume.

Since terahertz (THz) wave spectroscopy has been utilized to detect a number of chemical and explosive materials and related compounds by providing their spectral signatures in the THz frequency range, there is an interest in THz wve spectroscopy as a technique to sense improvised explosive devices. However, due to the severe water vapor attenuation of THz waves in the atmosphere, the reliable sensing range of THz wave spectroscopy has been limited to relatively short distances.

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.

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.