Photothermal nano-cavities for ultra-sensitive chem-bio detection

Abstract

Nano-cavity photothermal spectroscopy is a novel technique for ultra-sensitive chem-bio detection. We illustrate that through simultaneous localization of optical and thermal interactions in a planar nano-cavity, detection sensitivity can be improved by > 10[superscript 4] compared to state-of-the-art. Key to nano-cavity photothermal sensing is the use of novel infraredtransparent chalcogenide glasses for resonant cavity fabrication, as these glasses feature a photothermal figure-of-merit over two orders of magnitude higher than conventional materials. We demonstrate planar optical resonant cavity devices in these glasses with record cavity quality factors up to 5 × 10[superscript 5], leading to high photothermal detection sensitivity.