Asymmetry-Enabled Dual-Resonant Mid-Infrared Absorption in Subwavelength Perforated Metal Structures

Area of Science:

• Optics and Photonics
• Materials Science
• Nanotechnology

Background:

• Engineering multiresonant absorption in the midwave infrared (MWIR) is crucial for advanced detection and sensing.
• Existing methods often lack precise control over spectral response and line width.

Purpose of the Study:

• To design and fabricate thin metal absorbers with polarization-dependent, multiresonant spectral responses.
• To exploit the coexistence of conventional and geometry-enabled resonances for tailored optical properties.

Main Methods:

• Utilized a single, dilute-metal structure with anisotropic geometry.
• Exploited symmetry breaking to induce geometry-enabled resonances.
• Investigated the coexistence of Fabry-Peròt (FP) and symmetry-driven resonances.

Main Results:

• Achieved polarization-dependent absorption with distinct resonances for orthogonal polarizations.
• Demonstrated dual-resonant behavior arising from two fundamental physical mechanisms.
• Experimentally verified the design and fabrication of dual-resonant thin metal structures.

Conclusions:

• The developed thin metal absorbers offer independent tailoring of spectral position and line width.
• This approach provides a compact and versatile platform for MWIR detection and sensing applications.
• Findings pave the way for novel optical filters and spectral sensors.