**THz: Research Frontiers for New Sources, Imaging and Other Advanced Technologies**

Editors

**Stefano Lupi Akinori Irizawa Augusto Marcelli**

MDPI • Basel • Beijing • Wuhan • Barcelona • Belgrade • Manchester • Tokyo • Cluj • Tianjin

*Editors* Stefano Lupi Sapienza University of Rome Italy

Akinori Irizawa Osaka University Japan

Augusto Marcelli Istituto Nazionale di Fisica Nucleare—Laboratori Nazionali di Frascati Italy

*Editorial Office* MDPI St. Alban-Anlage 66 4052 Basel, Switzerland

This is a reprint of articles from the Special Issue published online in the open access journal *Condensed Matter* (ISSN 2410-3896) (available at: https://www.mdpi.com/journal/ condensedmatter/special issues/Terahertz spectroscopy).

For citation purposes, cite each article independently as indicated on the article page online and as indicated below:

LastName, A.A.; LastName, B.B.; LastName, C.C. Article Title. *Journal Name* **Year**, *Volume Number*, Page Range.

**ISBN 978-3-0365-2163-3 (Hbk) ISBN 978-3-0365-2164-0 (PDF)**

Cover image courtesy of Stefano Lupi.

© 2021 by the authors. Articles in this book are Open Access and distributed under the Creative Commons Attribution (CC BY) license, which allows users to download, copy and build upon published articles, as long as the author and publisher are properly credited, which ensures maximum dissemination and a wider impact of our publications.

The book as a whole is distributed by MDPI under the terms and conditions of the Creative Commons license CC BY-NC-ND.
