Lateral shift in photon tunneling studied by the energy streamline method

Abstract

The energy streamline method based on the Poynting vector of the coupled forward and backward waves is used to study photon tunneling phenomenon associated with the lateral shift of energy path. Each point on the energy streamline indicates the direction of the net energy flow of a plane wave. In the tunneling configuration, the light energy of the propagating waves is squeezed to the inside of a cone, whereas the streamlines of the coupled evanescent waves go through the barrier inside or outside the cone. This observation provides insight of the photon tunneling phenomenon. A relationship between the energy refraction angle and the incidence angle exists in the proximity limit and can be used to evaluate the lateral shift of the energy path. Furthermore, the energy streamline method can help gain deeper understanding of nanoscale radiation where photon tunneling plays an important role in the heat transfer enhancement.