Hybrid plasmonic waveguides (HPWs) are capable of supporting subwavelength optical modes. In a composite HPW (CHPW), the propagation loss can be minimized by adjusting the geometrical parameters of its component layers to reduce field flux inside its lossy metal layer. A ring resonator-based plasmonic sensor based on a waveguide structure of suspended CHPW (SCHPW) is designed for gas sensing applications. SCHPWs are applied for the introduced sensor’s 200-nm-wide bus waveguide and 1-μm-radius ring resonator. The operational parameters of the sensor, such as sensitivity and figure of merit (FOM), are investigated in the near-infrared region using a three-dimensional finite-difference time-domain method. For two considered resonances of the proposed sensor, sensitivities of 236.2 and 270 nm / RIU with FOMs of 67.4 and 37.5 RIU − 1 are achieved, respectively. Additionally, for the proposed sensor, a straightforward mechanism for sensing the mass density of the polarizable hydrogen gas is introduced using the theoretical index–density relation of Lorentz–Lorenz. The mass density sensitivities of 358.2 and 409.3 nm / ( g / cm3 ) are achieved for the two considered resonances for the hydrogen gas at the range of 0 to 0.05 g / cm3.

中文翻译：

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基于悬浮复合混合等离子体波导的折射率传感器的设计与仿真，用于传感可极化氢气的质量密度

混合等离子体波导 (HPW) 能够支持亚波长光学模式。在复合 HPW (CHPW) 中，可以通过调整其组件层的几何参数来减少有损耗金属层内的场通量，从而最大限度地减少传播损耗。基于悬浮 CHPW (SCHPW) 波导结构的环形谐振器等离子体传感器专为气体传感应用而设计。SCHPW应用于所推出的传感器的200nm宽总线波导和1μm半径环形谐振器。使用三维时域有限差分法在近红外区域研究传感器的操作参数，例如灵敏度和品质因数 (FOM)。对于所提出的传感器的两个考虑的谐振，实现了 236.2 和 270 nm / RIU 的灵敏度，FOM 分别为 67.4 和 37.5 RIU − 1，分别。此外，对于所提出的传感器，使用洛伦兹-洛伦兹的理论折射率-密度关系引入了一种用于感测可极化氢气质量密度的简单机制。对于氢气在 0 至 0.05 g/cm3 范围内的两个所考虑的共振，获得了 358.2 和 409.3 nm/(g/cm3) 的质量密度灵敏度。