A biosensor for detecting DNA hybridization via refractive index sensing has been demonstrated using a subwavelength grating (SWG) waveguide. Waveguide dimensions are selected by parametric optimizations to increase the mode-analyte overlap with considerations of typical silicon-on-insulator fabrications technology. DNA layer is added with a linker layer on silicon pillars of the SWG waveguide to optimize and detect the DNA hybridization. Some essential characteristics such as mode overlap factor, change in effective refractive index, waveguide sensitivity, and shift in resonance wavelength are computed for the different dimensional parameters of the SWG waveguide in DNA hybridization along with mode field intensity and normalized power using the finite element method. The DNA hybridization is shown by variation in normalized power of interacting light in cladding region of the waveguide for 0% to 100% fractional change of dsDNA and ssDNA. Waveguide sensitivity, shift in resonance wavelength, device sensitivity, and intrinsic limit of detection are obtained to ∼ 0.157, 7.01, 605 nm/RIU, and 1.30 × 10⁻⁴ RIU, respectively, for the optimized structure of SWG waveguide in sensing of DNA hybridization, which could be suitable aspects for detecting DNA hybridization.

已经使用亚波长光栅 (SWG) 波导演示了一种通过折射率传感检测 DNA 杂交的生物传感器。通过参数优化选择波导尺寸，以增加模式分析物重叠，同时考虑到典型的绝缘体上硅制造技术。DNA 层在 SWG 波导的硅柱上添加了连接层，以优化和检测 DNA 杂交。使用有限元方法计算 DNA 杂交中 SWG 波导的不同维度参数以及模场强度和归一化功率等一些基本特征，例如模式重叠因子、有效折射率的变化、波导灵敏度和共振波长的偏移. 对于 dsDNA 和 ssDNA 的 0% 至 100% 分数变化，通过波导包层区域中相互作用光的归一化功率的变化来显示 DNA 杂交。波导灵敏度、共振波长偏移、器件灵敏度和检测固有极限达到 ∼ 0.157、7.01、605 nm/RIU 和 1.30 × 10^-4 RIU 分别用于 SWG 波导在 DNA 杂交传感中的优化结构，这可能是检测 DNA 杂交的合适方面。