Analysis of Refractive Index Sensing Properties of Independently and Arbitrarily Tunable Multiplexed Compound Supercell Gratings

Abstract In terms of resonant characteristic regulation, although traditional micro- and nanostructures have been extensively investigated, achieving independent and arbitrary tuning of resonant position and intensity remains a significant challenge. Even in cases where certain structures allow for independent modulation, overlapping resonant modes often reduce the efficiency of light capture and absorption. To address this issue, we propose a three-dimensional (3D) multi-period Supercell structure capable of efficiently and independently controlling optical properties across multiple resonant wavelengths. Based on the waveguide resonant mode, by precisely adjusting structural parameters, the enhanced local field can be confined within individual periodic units, thereby enabling independent and arbitrary control over multiple resonant wavelengths. Under TM polarization, when the refractive index increases from 1.05 to 1.3 (Δn = 0.05), the resonance rate intensity changes are (ΔR₁, ΔR₂) = (0.13, 0.03), and the resonant wavelength shifts are (Δλ₁, Δλ₂) = (7.4, 10.2) nm. The corresponding refractive index sensitivity is (S1, S2) = (149, 204) nm/RIU. This study not only provides new insights into the design of photoluminescent materials but also facilitates the integration of multiple devices, such as multi-band independently and arbitrarily controllable optical filters, sensors, and photodetectors, within a broad spectral range, making it suitable for detecting multiple single analytes.