Abstract

Infrared (IR) absorption spectroscopy of molecular vibrations is of importance in material/medical science and security detection, since it provides essential information of the molecular structure, composition, and environment. For the versatile applications in prompt/easy-to-use inspection technologies, direct (far-field) detection of extremely small amounts of molecules is required. Surface-enhanced IR absorption (SEIRA) has been extensively studied and dramatic improvements of the sensitivity by several orders of magnitude were demonstrated using a tailored plasmonic nanostructures [1-5]. Here, we demonstrate background-suppressed resonant SEIRA of a self-assembled monolayer (SAM) chemisorbed on a metamaterial IR absorber [6,7]. Our metamaterial approach allows for a low-background detection scheme with significant plasmonic enhancement, thus further lowering the detection limit of direct IR absorption spectroscopy.

© 2014 Japan Society of Applied Physics, Optical Society of America