Terahertz frequency sensing has a unique part to play in the detection and identification of materials and objects. This frequency range, corresponding to a wavelength of around 0.1 mm, can be used to identify materials from their molecular spectra and to produce images of concealed objects. Terahertz spectra of drugs of abuse and explosives presented by a number of the contributing authors show that the presence of these materials can be detected in envelopes, packages and through clothing.

The technology of terahertz detection has largely been developed around expensive and bulky femtosecond laser systems but, as described in this book, advances in semiconductor superlattice technology are leading to compact electronic sources such as the quantum cascade laser, two-terminal Gunn type oscillators and even a THz frequency amplifier. These advances towards electronic (as opposed to optical) THz systems mean that the technology will become portable and much less costly.

Terahertz remote sensing is also discussed with the possibility of detection over distances of up to 30m using existing technology or even through the use THz waves generated locally in the vicinity of a target using only air as the transducer.

Comprehensive discussion on terahertz sensing for security purposes State-of-the art chapters on terahertz devices State-of-the art chapters on terahertz systems Expert opinions on the possibilities and practicalities of terahertz sensing

Inhalt
Devices.- Terahertz Emission from Semiconductors Excited by Ultrafast Laser Pulses.- Terahertz Generation by Multiplication.- Towards Superlattice Terahertz Amplifiers and Lasers.- Tailoring the Emission of Terahertz Quantum Cascade Lasers.- Guided Propagation of Terahertz Pulses on Metal Wires.- Superlattice and Other Negative-Differential-Resistance Devices: Current Status.- Interactions with Materials.- Molecular and Organic Interactions.- Terahertz Beam Interactions with Amorphous Materials.- Development of Tagless Biosensors for Detecting the Presence of Pathogens.- Detection and Sensing.- Improvements to Electronic Techniques for Terahertz Spectroscopic Detection.- Terahertz Time-Domain Spectroscopy of Crystalline and Aqueous Systems.- Continuous-Wave Terahertz Photomixer Systems for Real-World Applications.- Systems for Security.- Systems Requirements for A Multi-Channel Terahertz Contraband Scanner.- Challenges to Terahertz Counter-Terrorism and Security-Related Applications.- Terahertz Detection of Illegal Objects.- Terahertz Rays to Detect Drugs of Abuse.- Terahertz Spectroscopy for Explosive, Pharmaceutical, and Biological Sensing Applications.- Terahertz Communications: A 2020 vision.- Overview.- Applied Terahertz Science: The Technology of the Future, and Always Will Be?.