Enhancement of scattering of surface plasmon polaritons by surface defects: Technique and results

The intensities of scattering of surface plasmon polaritons by regular surface structures significantly exceed (by several orders of magnitude) the intensities of scattering of evanescent surface waves from these structures. When plasmon polaritons are scattered by diffraction grating grooves a few micrometers wide, the scattering from the trailing edge of a grating groove greatly exceeds the scattering level from the groove leading edge. Some of our original developments are presented that make it possible to put into effect an inexpensive software-hardware optical complex with a wide dynamic range, high sensitivity, and digital lock-in detection based on the use of a computer sound card.