One typical attribute of typical all-dielectric terahertz metamaterials is their thickness, which is designed to be dozens of, and even 100 microns, to scale back the leakage of the resonant area to the substrate. Within the frequency vary of two THz to three THz, we suggest a substrate-free ultra-thin all-dielectric terahertz metamaterial (UATM) composed of a silicon (Si) dual-ellipse array and silicon dioxide (SiO2) supporting layer with thicknesses of 5 μm and a pair of μm, respectively. The UATM displays quasi-bound state within the continuum (quasi-BIC) modes associated to the lean angle and interval parameters. Furthermore, as a result of robust electromagnetic area close to the interfaces and huge interplay space, the UATM displays a excessive refractive index sensitivity exceeding 1.00 THz per RIU. Moreover, at indirect incident angles starting from 0° to 25°, the resonant high quality issue (Q-factor) of the UATM stays increased than 100, and the sensitivities to the incident angle are 22.53 and 26.17 GHz per diploma with a linear vary of 0.498 THz and 0.438 THz, respectively. These properties point out the potential functions of the UATM in excessive sensitivity biochemical sensing and multifunctional narrowband filtering fields.
