The advent of nanotechnology has profound influence on the development and applications of new
types of lanthanide materials. Especially in the photonic industry, lanthanide based luminescent materials
play a very important role in several advanced technological applications. Some of their practical applications
include displays, lighting devices, lasers, fiber-optics, security inks and tags, optical sensors, drug
delivery, bioimaging, therapy, photocatalysis, and microscopy. Though there are several other luminescent
materials such as organic dyes and quantum dots utilized for these applications, lanthanide-based materials
deserve special attention due to their important features such as sharp absorption, emission, longer decay
time, photostability, less toxicity, etc. In this context, this special journal volume attempts to explore
some of the recent developments in the photonics and technological applications of rare earth doped materials.
This special issue contains six articles, divided into two volumes. The second volume Vol: 9, No. 3,
2019 contains three articles listed below. Optical properties of Erbium doped hydroxyapatite particle was
reported by Pooja Gitty et al. [1]. Second article by Dr. Kumar is a comprehensive review article on the
spectroscopy of near infrared emitting Nd,Er and Tm with particular emphasis on their applications in telecommunication
and biomedical sensors [2]. Third article by Solange et al. [3] report the upconversion
spectral properties of hydrothermally synthesized Ytterbium, Erbium and Thulium doped Y2O3.