Wednesday, August 3, 2011

Terahertz Wave Applications Using Photonic Technologies



MY NOTE: I'M INCLUDING THE ABSTRACT AND INTRODUCTION TO THIS PIECE WHICH IS TOO LARGE TO REPOST HERE, BUT YOU CAN READ THE ENTIRE DISCUSSION, IN THE PDF LINK, BELOW.  MUCH OF IT IS CERTAINLY TOO TECHNICAL FOR THE LAY COMMUNITY, BUT THE GENERAL CONCEPTS ARE PRETTY EASY TO FOLLOW.



Terahertz Wave Applications Using Photonic Technologies



Ho-Jin Song


1, Katsuhiro Ajito1, Naofumi Shimizu1, Naoya Kukutsu1, and Tadao Nagatsuma2





Microsystem Integration Labs., NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi, Kanagawa 243-0198, Japan



E-mail: song.hojin@lab.ntt.co.jp
Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan,



Abstract
We present a potential of photonic technologies originally developed for fiber-optic communications for use in



contemporary terahertz-wave applications and demonstrate several examples, including a high-precision timecontinuous


terahertz-wave signal and terahertz-wave band noise generators, sensing and imaging with CW and noise

signals, and wireless communications. In addition, recent progress of uni-travelling photodiodes, key component of this

work, is also presented.



1. Introduction



Terahertz (THz) waves, which lie in the frequency range of 0.1 ~ 10 THz, have long been investigated in a few


limited fields, such as astronomy, because of a lack of devices for their generation and detection. Several technical

breakthroughs made over the last couple of decades now allow us to radiate and detect terahertz waves more easily,

which has triggered the search for new uses of THz waves in many fields, such as bio-science, security, and information

and communications technology [1]. However, today’s THz technologies still rely on complex and bulky equipment,

which is not suitable for practical use, especially in outdoor sensing and wireless communications applications.

For compact and reliable THz-wave applications, we have been investigating the possibility of using photonic

technologies, which were originally developed for fiber-optic communications and are therefore inexpensive, compact,

and reliable. In this report, we will present our recent progress in THz-wave applications using photonic technologies,

such as high-precision time-continuous THz-wave signal and THz-wave band noise generators, spectroscopy and

imaging systems with the CW and noise signals, noise characterization of electronic devices, and wireless

communications.

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