Strong Coupling of Molecular and Mid-Infrared Perfect Absorber Resonances

We demonstrate strong coupling between a mid-infrared perfect absorber and a molecular absorption resonance embedded in our absorber structure. Anti-crossing behavior is demonstrated as the perfect absorber resonance is tuned through the molecular absorption line, both experimentally and numerically, and is described analytically using a simple coupled harmonic oscillator model. Excellent agreement between experimental, numerical, and analytical results are shown. Such devices offer potential for mid-infrared sensing systems and actively tunable perfect absorber devices.