Enhancing the Terahertz Absorption Spectrum Based on the Low Refractive Index All-Dielectric Metasurface

We presented an angle-multiplexing low refractive index dielectric metasurface for terahertz absorption spectrum enhancement of lactose with high Q resonance properties. The unit cell structure of the acrylonitrile butadiene styrene (ABS) square structure is designed and optimized. The resonant peak shifts of the dielectric metasurface are analyzed by changing the incident angle of the terahertz wave. Then the alpha-lactose films with different thicknesses are added to investigate the enhancement effect. The resonant peak amplitude of the angle-multiplexing low refractive index dielectric metasurface absorption spectrum changes greatly with the absorption spectrum of the samples. The results illustrate that the enhanced absorption spectrum formed by the linked envelope can be up to 45 times stronger than that without the unit cell structures and also exhibits a high-quality factor. The proposed dielectric metasurface provides great potential in enhancing the terahertz absorption spectrum.