研究目的
To design and fabricate an ultra-narrow band perfect metamaterial absorber based on dielectric-metal periodic configuration for near infrared spectral region, with characteristics such as nonpolarizing absorption peaks and tunable spectra.
研究成果
The ultra-narrow band PMA based on dielectric-metal periodic configuration is successfully designed and fabricated, demonstrating nonpolarizing absorption peaks, insensitivity to incident angle under TE polarization, and large spectral tunability under TM polarization. Experimental results align with theoretical simulations, showing high Q-factors and narrow bandwidths. This PMA has potential applications in tunable filters, sensors, and optical signal processing.
研究不足
The PMA's performance may be limited by fabrication imperfections, such as deviations in layer thicknesses and grating periods, which can affect absorption peak accuracy and Q-factors. Additionally, the structure's sensitivity to polarization and incident angle under TM illumination might restrict applications requiring stable performance across all conditions.
1：Experimental Design and Method Selection:
The PMA is designed using rigorous coupled-wave analysis (RCWA) and finite-difference time-domain (FDTD) simulations. It consists of a dielectric resonant structure (2D grating layer and two waveguide layers) and a metal substrate. The design aims to achieve ultra-narrow band absorption through guided-mode resonance (GMR) effect and surface plasmon resonance.
2：Sample Selection and Data Sources:
A PMA sample is fabricated with specific structural parameters (e.g., periods Λx=555 nm, Λy=595 nm, fill factor f=0.6, layer thicknesses d1=90 nm, d2=190 nm, d3=150 nm). Materials include Si3N4, ITO, and Au.
3：6, layer thicknesses d1=90 nm, d2=190 nm, d3=150 nm). Materials include Si3N4, ITO, and Au.
List of Experimental Equipment and Materials:
3. List of Experimental Equipment and Materials: Equipment includes a sputtering system for thin-film deposition, electron beam lithography system for patterning, atomic force microscopy (AFM) for profile measurement, halogen lamp light source, collimating lens, calcite crystal polarizer, rotation stage, and spectrometer. Materials include Si3N4, ITO, Au substrate, and electron beam resist.
4：Experimental Procedures and Operational Workflow:
Fabrication involves depositing ITO and Si3N4 layers on Au substrate, patterning the grating using electron beam lithography and reactive ion etching, and removing residual resist. Characterization involves measuring reflection spectra at various incident angles and polarizations, and calculating absorption spectra.
5：Data Analysis Methods:
Absorption is calculated as A(λ) = 1 - R(λ), where R(λ) is the measured reflectance. Q-factors are computed using central frequency and FWHM. Simulations are validated with FDTD software.
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