Preface to the second special issue on Terahertz Wave Science, Technology, and Application

Abstract

Terahertz (THz) frequency region has attracted considerable interest, due to its unique nature and promising applications. A number of breakthroughs were achieved by the worldwide research groups in this field, including high-performed sources, detectors, functional devices, interaction with materials as well as applications. Previously, the first special issue on “Terahertz Wave Science, Technology, and Application” was presented (June 2014). This is the second special Issue with 3 review articles and 8 research articles, which introduce and discuss recent developments of relevant subjects. These papers can be divided into such categories: nonlinear optical response of grapheme, semiconductor activated metamaterials, superconducting metamaterials, THz generation with air and GaAs photoconductive antenna, double-probe-pulse THz detection, applications in sensing, imaging and spectroscopy, and so on. Prof. Chao Zhang and coworkers of University of Wollongong reviewed the recent developments of nonlinear optical response of graphene in THz and near-infrared frequency regime. Prof. Hou-Tong Chen of Los Alamos National Laboratory reviewed the recent progresses on semiconductor activated THz metamaterials. Prof. Weili Zhang and coworkers of Tianjin University reviewed the recent results on tailoring electromagnetic responses in THz superconducting metamaterials. In the research articles, Prof. Kun Zhao’s group of China University of Petroleum reported the detection of nheptane, n-octane and nitrate solutions with THz time-domain spectroscopy. Prof. Zhi Hong and coworkers of China Jiliang University investigated a high Q THz asymmetrically coupled resonator and its sensing performance. Prof. Alexander Shkurinov’s group of Lomonosov Moscow State University demonstrated the simultaneous generation of nonlinear optical harmonics and THz radiation in air: polarization discrimination of various nonlinear contributions. Prof. J. Bianca Jackson and coworkers of Ecole Polytechnique applied THz pulse imaging in archaeology. Dr. Haiwei Du of RIKEN investigated optical ionization evolution effect on photocurrent produced from two-color femtosecond laser pulses. Prof. Jinsong Liu’s group presented the studies on the behavior of GaAs photoconductive antenna. The articles in this special issue have certain significance for promoting the development of THz technology. It is hoped that the second special issue will benefit THz applications. On behalf of the editorial committee, we express our sincere thanks to all the authors and reviewers for their great contribution to this special issue. Also, we thank the editorial committee members for their excellent assistance. Finally, we are grateful to the editorial staff for their help, also thanks for my research assistants Dr. Pengxiang Liu, Dr. Lanju Liang and Yating Zhang. Without all of the contributions of these hard-working, dedicated people, it would have been impossible to produce this second special issue.