THz Systems Exploiting Photonics and Communications Technologies

Abstract

Terahertz (THz) systems open up the possibility of new applications of electromagnetic waves. Enormous bandwidths up to several terahertz enable the development of powerful spectroscopy systems that can provide insights into the structure and material of objects with micrometer resolution. New high power and compact THz time-domain spectroscopy (TDS) systems will be presented. The wide bandwidth also enables high-resolution imaging under far-field conditions to analyze arbitrary objects from a distance. In addition, a near-field system-on-a-chip imaging system is presented that achieves a resolution of 10 μm. Additionally, the application of terahertz waves presents challenges due to the low transmit power of the sources, high attenuation in free space, and the high noise figures of the receivers. These challenges can be overcome by antennas with high gain. Since -depending on the application -spatial scanning or focusing in a time-varying direction is required, beam steering is an essential component of many THz systems. In terms of communications, terahertz carrier frequencies offer wide bandwidths, enabling correspondingly high data rates of 100 Gbit/s and more. As a result, the frequency bands between 250 GHz and 450 GHz have already been identified and/or allocated for communication services and are being discussed as a component of 6G mobile communications. Concepts and demonstrations for 6G terahertz mobile communications will be presented. The high bandwidth of terahertz waves can also be used for high-accuracy indoor localization.INDEX TERMS THz time-domain spectroscopy, high average power THz systems, THz far-field imaging, THz near-field imaging, THz communication, THz localization, MTT 70th Anniversary Special Issue.

Review of Bioplastics Characterisation by Terahertz Techniques in the View of Ensuring a Circular Economy

“…This approach can be further divided into passive and active THz imaging. The working principle of these systems is described in detail in several studies and reviews [78][79][80][81][82][83][84][85], which categorise THz imaging systems in different ways, such as active vs passive, electronic vs optical, continuous wave vs pulsed, transmission vs reflection, near-field vs far-field, or single-pixeled vs multi-pixeled.…”

High-throughput terahertz imaging: progress and challenges

“…Lying between the infrared and millimeter wave regimes, the terahertz frequency range is often referred to as the “terahertz gap”, because of the lack of efficient terahertz emitters and detectors. However, this gap is being gradually filled from both sides of the spectrum, as terahertz technology is developing in tandem with the more mature radio frequency (RF) and photonics industries 1 , 2 . The unique properties of terahertz waves have prompted numerous compelling applications.…”

Terahertz Spectroscopy for Non-Destructive Solid-State Investigation of Norfloxacin in Paper Tablets after Wet Granulation

“…THz TDS uses electromagnetic waves in a frequency region that is located between infrared and microwaves. Typical THz TDS instruments enable the investigation in the frequency range from 0.1 to 4 THz, approximately [ 22 ]. It is a fast and non-destructive method that can be used in several research areas, such as medicine, engineering, material sciences and chemistry [ 22 , 23 , 24 , 25 ].…”

“…Typical THz TDS instruments enable the investigation in the frequency range from 0.1 to 4 THz, approximately [ 22 ]. It is a fast and non-destructive method that can be used in several research areas, such as medicine, engineering, material sciences and chemistry [ 22 , 23 , 24 , 25 ]. In reference [ 26 ] a comprehensive overview of THz science and technology as well as numerous fields of applications is given.…”