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

Abstract

I am delighted to introduce the first special issue on Terahertz (THz) Wave Science, Technology, and Application. This issue contains five review and research papers, all written by former Ph.D students, Dr. Xiaofei Lu, Dr. Jingle Liu, Dr. Benjamin Clough, Dr. I-Chen Ho, and Dr. Yuting W. Chen, at the Center of THz Research, Rensselaer Polytechnic Institute. These gifted scientists and engineers are among the most brilliant students that have graduated in the THz community in the past four years. This issue covers research frontiers from THz antireflection silicon structure (Dr. Chen), remote sensing (Dr. Liu), and THz wave air photonics (Dr. Lu) to nonlinear THz wavematter interaction (Dr. Ho), and THz enhanced acoustics (Dr. Clough). THz radiation, which is electromagnetic radiation in a frequency interval from 0.3 to 10 THz (1 mm–30 μm wavelength), is the next frontier in science and technology. This band occupies a large portion of the electromagnetic spectrum between the infrared and microwave bands. Basic research, new initiatives, and developments in advanced sensing and imaging technology, with regards to the THz band, remain largely unexplored compared to the relatively well-developed science and technology in the microwave and optical frequencies. Historically, THz technologies were used mainly within the astronomy community for studying the background of cosmic far-infrared radiation, and by the laser-fusion community for the diagnostics of plasmas. Since the first demonstration of THz wave time-domain spectroscopy in the late 1980’s, there have been a series of significant advances (particularly in recent years). More intense THz sources and higher sensitivity detectors are providing new opportunities for understanding the basic science in the THz frequency range. As developments move forward, THz science will not only have an impact on material characterization and identification. It will also have potential applications in the fields of communications, imaging, medical diagnosis, health monitoring in environmental, chemical, and biological sensing, as well as security and quality control applications. Twenty-first century research in the THz band is one of the most promising areas of study for transformational advances in imaging and other interdisciplinary fields. The THz frequency range is the last segment of the electromagnetic spectrum to be conquered. Far from being fully explored, it offers great opportunities in science, innovation, new technology and applied fields. I thank many colleagues and friends for their guidance, support, and friendship. Special thanks to Dr. David Auston, Dr. Chi Lee, Dr. Dan Grischkowsky, Dr. Dan Mittleman, Dr. Peter Siegel, Dr. Qing Hu, Dr. Keith Nelson, Dr. Charles Schmuttenmaer, Dr. Peter Jepsen, Dr. Paul Planken, Dr. Kiyomi Sakai, Dr. Cunlin Zhang, Dr. Jianquan Yao, Dr. Jinsong Liu, Dr. Gun-Sik Park, and Dr. Alexander Shkurinov. I would like to thank those former students who have graduated from my THz group at Rensselaer: Ms. Yahong Jin, Ph.D, 1994; Mr. Xinfa Ma, Ph.D, 1995; Mr. Greg Wagoner, Ph.D, 1997; Mr. Qi Wu, Ph.D, 1997; Ms. Jennifer Riordan, Ph.D, 1998; Mr. Ming Li, Ph.D, 2000; Mr. Pengyu Han, Ph.D, 2000; Mr. F. G. Sun, Ph.D, 2001; Mr. Qin Chen, Ph.D, 2001; Mr. Kwang-Su Lee, Ph.D, 2002; Mr. Shaohong Wang, Ph.D, 2003; Ms. Fatemah M. Al-Douseri, Ph.D, 2005; Mr. Kai Liu, Ph.D, 2005; Mr. Haibo Liu, Ph.D, 2006; Mr. Tao Yuan, Ph.D, 2006; Ms. Hua Zhong, Ph.D, 2006; Mr. Xu Xie, Ph.D, 2007; Mr. Brian Schulkin, Ph.D, 2008; Mr. Nick Karpowicz, Ph.D, 2009; Mr. Jian Chen, Ph.D, 2009; Mr.