Experimental Demonstration of Surface Plasmon Michelson Interferometer at the Novosibirsk Terahertz Free-Electron Laser

Here we present experimental results of testing the surface plasmon (SP) Michelson interferometer in the terahertz range using free-electron laser radiation. The device is designed for study of thin-layer samples on a conductive substrate. The interferometer consists of flat mirrors and a transparent plate for reflection and splitting of SP beams. The interference pattern in this device is formed by SPs. The results of the experiments have shown that the real and imaginary parts of the refractive index of the SPs propagating along a plane metal with a dielectric coating can be determined.