Refraction index sensor based on phase resonances in a subwavelength structure with double period

Area of Science:

• Photonics and Nanotechnology
• Optical Sensing
• Materials Science

Background:

• Subwavelength structures offer unique optical properties.
• Phase resonance is a key phenomenon for optical sensing.
• Accurate refractive index sensing is crucial in various scientific fields.

Purpose of the Study:

• To numerically demonstrate a novel refraction index sensor.
• To utilize phase resonance excitation in a bi-periodic subwavelength-slit structure.
• To achieve high-precision refractive index determination.

Main Methods:

• Numerical simulation of a bi-periodic subwavelength-slit structure.
• Excitation of phase resonance modes.
• Analysis of transmitted intensity peaks.
• Correlation of peak shifts with refractive index variations.

Main Results:

• The sensor detects refractive index variations via shifts in transmitted intensity peaks.
• Spectral position of resonant peaks shows linear or quadratic dependence on refractive index.
• High precision is achieved for unknown refractive index values.
• The device demonstrates scalability across different wavelength ranges.

Conclusions:

• The proposed subwavelength-slit structure functions as an effective refraction index sensor.
• Phase resonance excitation enables precise and scalable optical sensing.
• The sensor design offers a versatile platform for various applications requiring refractive index monitoring.