Harmonic minimization method for plasmonic diffraction grating sensor design

The design of diffraction gratings is a critical challenge in numerous fields of applied optics, including integrated optics, spectroscopy, and plasmonics. This work introduces a strategy for optimizing the design of diffraction-based plasmonic sensors. The proposed harmonic minimization method bridges low-complexity diffraction formalisms with structures that are more feasible for fabrication using widely adopted manufacturing processes. This method is applied in the design of palladium (Pd) gratings for hydrogen gas sensing within the infrared spectrum. The performance of the designed structure is evaluated by comparing its reflectance spectrum and sensitivity to those of a fabricated device. It is shown that the proposed algorithm can obtain structures with similar sensitivity to those obtained by the Chandezon method with low computational complexity for rectangular and triangular profiles. Conditions of applicability in alternative profiles are discussed.