Nanoperiodic optical sensors with a giant enhancement of Raman scattering by IR excitation

To increase Raman scattering, we developed nanostructures of the “photonic crystal” type, which are a periodic array of SiO2 dielectric columns covered with a thick layer of metal. We studied columns with a cross section in the form of squares, circles, rectangles, and triangles in order to optimize the geometry of the nanostructures. The planar size of the columns varied in a range of 300-600 nm, the gap between themis in a range of 300-600 nm, the height of the columns - from 50 to 1000 nm, and the silver thickness varied from 40 to 200 nm. We demonstrated the possibility of smooth adjustment of the plasmon absorption resonance of the combined metal- dielectric structure to the laser wavelengths of 785 and 1064 nm.