Surface-Enhanced Thermal Emission Spectroscopy with Perfect Absorber Metasurfaces

Surface-enhanced spectroscopy techniques using plasmonic nanoantennas or metasurfaces help to reduce the detection limit for biochemical sensing. While infrared spectroscopy is an excellent tool to identify a molecular species, a typically expensive IR light source is needed. We report a surface enhanced spectroscopy technique based on the thermal emission of III-V semiconductor metasurfaces. The presence of a molecular species grafted on the surface modulates the emission spectrum analogously to the modulation achieved in surface-enhanced infrared absorption (SEIRA) spectroscopy. The vibrational fingerprint of the molecular species is detected due to the electromagnetic field enhancement obtained with a plasmonic metasurface. Because the metasurface acts simultaneously as radiation source and sensor chip, the experimental setup is simplified and therefore more compact and potentially more cost-efficient. This novel approach of surface-enhanced thermal emission spectroscopy (SETES) is appealing for miniaturized and integrated molecular sensing devices.