Selective multi-wavelength infrared emission by stacked gap-plasmon thermal emitters

Area of Science:

• Photonics and Plasmonics
• Infrared Spectroscopy
• Nanomaterials

Background:

• Selective multi-wavelength infrared light sources are crucial for precise molecular detection via vibrational spectra.
• Existing technologies face limitations in achieving simultaneous multi-wavelength emission for complex sensing applications.

Purpose of the Study:

• To design and demonstrate a novel double-stacked cross-shaped metal-dielectric-metal (MDM) resonator for penta-wavelength mid-infrared thermal emission.
• To investigate the tunability and polarization properties of the proposed MDM resonator for advanced sensing applications.

Main Methods:

• Fabrication of a double-stacked cross-shaped MDM resonator with optimized un-symmetric cross-shaped tri-layers and sandwiched dielectric materials.
• Characterization of the mid-infrared thermal emission spectra and analysis of magnetic resonances.
• Utilizing a polarization rotator to tune the emission wavelengths.

Main Results:

• Achieved penta-wavelength mid-infrared thermal emission from the optimized MDM resonator.
• Observed four distinct emission bands attributed to magnetic resonances and one peak from silicon dioxide phonon emission.
• Demonstrated polarization-dependent and non-dispersive emission properties due to localized plasmon oscillations.
• Successfully tuned emission wavelengths from 4.5-7.5 μm to 5.5-8.5 μm using a polarization rotator.

Conclusions:

• The proposed MDM resonator enables simultaneous detection of multi-band molecular absorption fingerprints.
• Tunable, polarization-dependent emission wavelengths facilitate multi-compound sensing within a compact system.
• This work offers a promising platform for advanced molecular detection and chemical sensing applications.