Mid-infrared, long-wave infrared, and terahertz photonics: Introduction

This feature issue presents recent progress in long-wavelength photonics, focusing on wavelengths that span the mid-infrared (3–50 µm), the long-wavelength infrared (30–60 µm), and the terahertz (60–300 µm) portions of the electromagnetic spectrum. The papers in this feature issue report recent progress in the generation, manipulation, detection, and use of light across this long-wave region of the “photonics spectrum,” including novel sources and cutting edge advances in detectors, long-wavelength non-linear processes, optical metamaterials and metasurfaces, and molecular spectroscopy. The range of topics covered in this feature issue provide an excellent insight into the expanding interest in long-wavelength photonics, which could open new possibilities for basic research and applications in industries that span health, environmental, and security.