▎ 摘　　要

Sensing is to date one of the most successful applications of surface plasmons thanks to the exceptional field amplification and sensitivity of these modes in metallic nanostructures. Here we introduce a promising detection scheme based on the propagation of strongly confined antibonding plasmons supported by graphene sandwiches. Instead of measuring changes in the refractive index or enhancing a restricted number of molecular absorption lines, the proposed device can recover an extended portion of the infrared spectrum of a molecule. Moreover, the extreme compression of light in graphene means that a diluted 2 nm-thick analyte can cause up to 3 dB intensity changes. The broadband capability and sensitivity also imply that one can easily identify different chemicals in a mixture and extract their respective concentration. We conclude by presenting a simple experimental setup based on this mechanism for infrared spectroscopy that could become a cheap Fourier transform infrared accessory and an alternative to crystal-based attenuated total reflection spectroscopy.