Double-valley calibration plasmon refractive index sensor and implementation method thereof

The invention discloses a double-valley calibration plasmon refractive index sensor and an implementation method thereof. According to the invention, a one-dimensional periodic metal slit array is formed on a transparent substrate; a two-dimensional reflectivity spectrum is obtained by scanning the wavelength and the incident angle, a coherence curve is calculated by using a coherence formula, and the wavelength lambda of the incident laser is selected through the two-dimensional reflectivity spectrum. Two coherent states in different directions are respectively obtained under the condition of meeting the coherence condition of the interface between the one-dimensional periodic metal slit array and the to-be-measured substance, and the two coherent state angles are subtracted to obtain the refractive index of the to-be-measured substance; according to the double-valley calibration plasmon refractive index sensor provided by the invention, the two valleys can move in opposite directions along with the change o