Tamm Plasmonic-Based Elliptical Anisotropic Photonic Crystals with Multifunctional Optical features

In recent years, multifunctional photonic structures have gained increasing interest due to their ability to perform diverse optical tasks within a single platform. In this work, we design and investigate a one-dimensional anisotropic photonic crystal that simultaneously exhibits high-performance optical sensing, filtering, nonreciprocal transmission, and an electromagnetically induced transparency (EIT)-like phenomenon. The structure consists of periodic layers of SiO₂ and a low-index medium with a refractive index ranging from 1.36 to 1.44, along with a thin gold film supporting the excitation of a Tamm Plasmon Mode (TPM). To enhance and diversify the optical functionalities, an elliptically anisotropic metamaterial layer is incorporated into the periodic stack. Numerical simulations reveal that the structure not only exhibits a sharp TPM-related resonance shift in response to refractive index changes but also functions as an effective narrowband optical filter. Furthermore, the presence of anisotropy introduces nonreciprocal transmission characteristics and enables the appearance of an EIT-like transparency window within the reflection spectrum. These results demonstrate the potential of this anisotropic photonic crystals as a compact and multifunctional platform for advanced photonic applications.