Introduction to the Issue on Current Trends in Terahertz Photonics and Applications

Since the last special issue on terahertz science and technology, nearly three years have been passed. During this period, while there have been further developments in terahertz (THz) sources, detectors, materials, and applications, there have been new discoveries. The purpose of this issue of the IEEE Journal of Selected Topics in Quantum Electronics (JSTQE) is to highlight the advances in materials, devices, and applications and new directions in the THz domain within the last three years. Broad technical areas include: 1) materials; 2) matamaterials, plasmonics, and plasmons; 3) techniques and effects; 4) generation and power scaling; 5) detectors; 6) devices; 7) applications. These key THz topics are discussed in both invited and contributed papers published in this issue, providing comprehensive overviews of the current status and future directions as well as publishing original results on research and recent developments on THz photonics and applications. This issue contains 28 papers including 12 invited and 16 contributed papers authored by both well-established research groups and emerging stars pioneering in the THz field all over the world. While the invited papers include extended reviews on recent THz research, the contributed papers cover a wide range of the cutting-edge research in the topics described earlier.