The terahertz (THz) band occupies a narrow region of the electromagnetic spectrum between the microwave and infrared frequency ranges. Owing to its distinctive propagation characteristics, low photon energy, and nonionizing nature, THz radiation is considered safe for biological systems and has attracted growing interest in scientific and technological research. In recent years, photonic crystal fibers (PCFs) operating in the THz regime have emerged as promising platforms for a wide range of applications, including sensing, imaging, and high‐speed communication. In this review, we present a comprehensive survey of recent developments in THz PCFs, focusing on their structural designs and practical applications. A systematic literature search was conducted using four major databases: Scopus, PubMed, IEEE Xplore, and ScienceDirect, to identify original research articles published between January 1, 2001, and November 15, 2023. The Preferred Reporting Items for Systematic Reviews and Meta‐Analyses methodology was employed, resulting in the detailed analysis of 122 relevant publications. The review highlights PCF geometries, background materials, performance evaluation parameters, and fabrication techniques, and concludes by outlining future research directions for PCF development in the THz spectrum.
Ferdous et al. (Wed,) studied this question.