Abstract
The development of small and highly efficient light sources such as quantum cascade lasers (QCL) and
fiber lasers emitting mid-infrared (IR) light have progressed rapidly. These lasers replace large solid /
gas mid-IR lasers and a weak lamp source used in spectroscopic applications. The advent of mid-IR
QCLs, fiber lasers, and other compact mid-IR lasers has enabled the miniaturization of laser treatment
equipment, the realization of mid-infrared imaging equipment, and the reduction in size and cost of diagnostic
/ healthcare systems using mid-IR spectroscopy. In this special issue, we will introduce light
source technologies that can be applied to biological application systems, and the latest technologies for
therapeutic, diagnostic, and healthcare applications.
