Fluctuation electromagnetic interactions and energy exchange in structured media Alejandro Rodriguez Princeton University We describe recent progress in the area of electromagnetic fluctuations at the nano-scale, including development of sophisticated, brute-force techniques for modeling van der Waals or Casimir interactions and radiative heat exchange in complicated geometries—combinations of molecules and structured surfaces separated by several to hundreds of nanometers—where both retardation and wave effects are relevant, leading to significant modifications and enhancements. Recently derived theoretical bounds/limits to these interactions and application of large-scale (topology) optimization to the related problem of enhancing emission from dipolar radiators near structured surfaces offer hope and reveal opportunities for further modifications and enhancements.