Molecular device turns infrared into visible light

Artistic view of the nanoparticle-in-groove plasmonic cavities. Credit: Nicolas Antille ( www.nicolasantille.com) - Researchers at EPFL, China, Spain and the Netherlands have built a micro-device that uses vibrating molecules to transform invisible mid-infrared light into visible light. The breakthrough ushers in a new class of compact sensors for thermal imaging and chemical or biological analysis. Image: Artistic view of the nanoparticle-in-groove plasmonic cavities. Molecules cover the gold film and are sandwiched between the groove and the 150-nm large nanoparticle. The infrared signal of interest comes from below the substrate while the pump laser providing energy for upconversion comes from the top. Both are focused by the cavity onto the molecules, and interact with their internal vibrations to generate an upconverted copy of the infrared signal at visible frequencies (bright spot).