Phonons Show Strong Interaction with Light

Researchers at Max Planck Institut für Biochemie report that lattice vibrations of polar dielectrics can enhance optical near-field coupling in the infrared. Described in the July 11 issue of Nature, the article notes that resonant coupling with lattice vibrations (phonons) is analogous to similar behavior in plasmons -- the coherent motion of conduction electrons. However, because phonon damping is weak within the SiC lattice, phonon resonances interact more strongly with light. Minor variations to the structural and chemical makeup of the SiC surface, such as a 10-nm-thick gold film, had a strong impact on the coupling characteristics.

Combined with scanning near-field microscopes, phonon-enhanced near-field optical resonance could help map surface variations with nanometer-scale spatial resolution.