Multi-Band Mid-IR Molecules Identification Using Plasmonic Metamaterials Induced by Bright-Dark Coupling

This paper reports a multi-band surface-enhanced molecular detection technique induced by bright-dark coupling in the mid-IR fingerprint region. Our device enables the excitation of four plasmonic resonances (
$3\mu\mathrm{m}, 5.6\mu \mathrm{m},\ 6.9\mu\mathrm{m}$
, and
$7.4\mu\mathrm{m}$
) covering an ultra-wide spectral range, which paves the way to molecule recognition from the whole IR fingerprint region. The multi-band plasmonic sensor with ultra-wide continuous resonance spectra can be used for a wide range of infrared molecular sensing applications with enhanced detection resolution and sensitivity.