Metamaterial-Based Electromagnetically Induced Transparency

Electromagnetically induced transparency (EIT) is a quantum interference effect that occurs in atomic physics systems, creating a sharp transparency window for the propagation of light through opaque media, analogous phenomena have recently been demonstrated in various engineering metamaterials, allowing for experimental observations using incoherent light at room temperature, which greatly enriches the connotation of EIT, stimulates research enthusiasm for metamaterial-based EIT (MBEIT). Timely summarizing the latest progress of MBEIT is crucial for promoting its vigorous development. Herein, a comprehensive and in-depth summary of the research progress on four core aspects of MBEIT, namely physical mechanisms, classifications, tunable functions, and applications is provided. Mainstream physical mechanisms of MBEIT, including Lorentz coupled model theory, bound states in the continuum, and three energy-level theory are briefly outlined. Classifications of MBEIT involve single-band, dual-band, multi-band, and broadband are further summarized. The MBEIT having dynamically tuned properties employing diversified modulation strategies, such as electrical, optical, thermal, and mechanical, is emphasized. Interdisciplinary application achievements of MBEIT in the fields of medicine, biochemistry, fingerprinting, optical encryption, and ultrafast optics are reviewed. The challenges and some solutions for the future research on MBEIT are finally discussed.