Improved performance of temperature sensors based on the one-dimensional topological photonic crystals comprising hyperbolic metamaterials

This paper seeks to progress the field of topological photonic crystals (TPC) as a promising tool in face of construction flaws. In particular, the structure can be used as a novel temperature sensor. In this regard, the considered TPC structure comprising two different PC designs named PC₁ and PC₂. PC₁ is designed from a stack of multilayers containing Silicon (Si) and Silicon dioxide (SiO₂), while layers of SiO₂ and composite layer named hyperbolic metamaterial (HMM) are considered in designing PC₂. The HMM layer is engineered using subwavelength layers of Si and Bismuth Germinate, or BGO ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow><mml:msub><mml:mtext>Bi</mml:mtext> <mml:mn>4</mml:mn></mml:msub> <mml:msub><mml:mtext>Ge</mml:mtext> <mml:mn>3</mml:mn></mml:msub> <mml:msub><mml:mtext>O</mml:mtext> <mml:mn>12</mml:mn></mml:msub> </mml:mrow> </mml:math> ). The mainstay of our suggested temperature sensor is mainly based on the emergence of some resonant modes inside the transmittance spectrum that provide the stability in the presence of the geometrical changes. Meanwhile, our theoretical framework has been introduced in the vicinity of transfer matrix method (TMM), effective medium theory (EMT) and the thermo-optic characteristics of the considered materials. The numerical findings have extensively introduced the role of some topological parameters such as layers' thicknesses, filling ratio through HMM layers and the periodicity of HMM on the stability or the topological features of the introduced sensor. Meanwhile, the numerical results reveal that the considered design provides some topological edge states (TESs) of a promising robustness and stability against certain disturbances or geometrical changes in the constituent materials. In addition, our sensing tool offers a relatively high sensitivity of 0.27 nm/°C.