https://www.photonics.com/Articles/Molecular_Qualities_Captured_with_Plasmons/a65930 Specific properties of small amounts of molecules can now be isolated with the use of graphene-metal film structures, thanks to the work of scientists in Russia and Spain. Their work focuses on a plasmon, which is an electron oscillation that is coupled with an electromagnetic wave. By focusing these plasmons, they are converted into those with shorter wavelengths, called acoustic plasmons.