Characteristics of light transfer in the connected conical waveguides with the same symmetry axis

The propagation of the light trough dielectric-metal-dielectric conical waveguide is described by the coupling modes between internal and external waveguides. The energy pumping from internal to the external waveguide has a resonant behavior and is very sensitive to the variations of the system parameters. The simplified model of this process realization is the light flash at the end of the conical metal covered tip of the optical fiber that crosses the liquid-air interface. Here, as an external waveguide serves the liquid meniscus formed at the tip of the optical fiber. In this condition, the shift of liquid surface by 50 nm toward the tip end brings significant changes in the transferred radiation power. Ability to register nanometric displacements (nanovibrations) of the liquid surface opens up new ways to create sensitive sensors for different purposes.