Showing posts with label R A Lewis. Show all posts
Showing posts with label R A Lewis. Show all posts

Wednesday, August 14, 2019

Abstract-A review of terahertz detectors


R A Lewis

https://iopscience.iop.org/article/10.1088/1361-6463/ab31d5/pdf

Physics is the interplay of energy and matter. Energy, in the form of light, interacting with matter, principally in the solid state, underpins this topical review. The subject is developed carefully and methodically, beginning with basic definitions pertaining to terahertz detectors and terahertz radiation, then proceeding systematically to delineate characteristics of terahertz photons and terahertz detectors in more detail. In-between, the intimate connection linking terahertz sensors and terahertz sources is highlighted—an important aspect unfortunately often overlooked or ignored when terahertz detectors are discussed in isolation. At the centre of this topical review are the various physical mechanisms by which electromagnetic radiation of terahertz frequencies interacts with matter. The logic is to present first the underlying physical principles of detection before presenting the practical implementation in a specific device, rather than the other way around. A taxonomy of terahertz detectors is then proposed based on the underlying physical principles of detection. Following on from this classification, state-of-the-art terahertz detectors are surveyed and appraised; this overview constitutes the longest section of the review. Key detector parameters which inform applications are then presented and tabulated. Finally, the present state-of-the-art is anchored within the wider scientific context of historical developments and future prospects.

Friday, August 29, 2014

Abstract-A review of terahertz sources





R A Lewis
Institute for Superconducting and Electronic Materials and School of Physics, University of Wollongong, Wollongong NSW 2522, Australia 
http://iopscience.iop.org/0022-3727/47/37/374001
Bibliometric data set the scene by illustrating the growth of terahertz work and the present interest in terahertz science and technology. After locating terahertz sources within the broader context of terahertz systems, an overview is given of the range of available sources, emphasizing recent developments. The focus then narrows to terahertz sources that rely on surface phenomena. Three are highlighted. Optical rectification, usually thought of as a bulk process, may in addition exhibit a surface contribution, which, in some cases, predominates. Transient surface currents, for convenience often separated into drift and diffusion currents, are well understood according to Monte Carlo modelling. Finally, terahertz surface emission by mechanical means—in the absence of photoexcitation—is described.