Giving SEIRA a Boost

New light-trapping sensor increases sensitivity of surface-enhanced infrared absorption spectroscopy devices – by up to 1,000 times

October 2017

The optical absorption spectra of trace chemical or biological molecules are typically very weak. Now, experts in material science, nano-optics and bio/chemical sensing have developed an optical device that is able to significantly enhance the absorption signal of trace molecules.

The collaborative team’s light-trapping structure can squeeze infrared light into sub-5-nm gaps with very high efficiency, resulting in a very strong localized light field. They then demonstrated an application of this “squeezed” light using surface-enhanced infrared absorption (SEIRA) spectroscopy. The sensor, which acts as a substrate for the materials being examined, was found to boost the ability of SEIRA devices to detect molecules at 100 to 1,000 times greater sensitivity than previously reported results.

  1. D Ji et al., “Efficient mid-infrared light confinement within sub-5-nm gaps for extreme field enhancement”, Adv Opt Mater, 5 (2017).