Optical fibers having metallic micro/nano-structure on end-facet, and fabrication method, and application method thereof

A fabrication method of an optical fiber having metallic micro/nano-structure on end-facet, wherein the method comprises at least the following steps:

• 1) providing a substrate and an optical fiber, fabricating, on the surface of the substrate, a metallic micro/nano-structure having a property of being weakly adherent to the substrate;
• 2) applying an adhesive on the end-facet of the optical fiber or the surface of the metallic micro/nano-structure;
• 3) adjusting the relative position of the optical fiber so that the end-facet of the optical fiber is aligned with the position of the metallic micro/nano-structure;
• and
• 4) exposing the adhesive under adhesive curing light where the curing light penetrates through the substrate and the metallic micro/nano-structure before it reaches the adhesive, so that the adhesive is cured and the cured adhesive binds the metallic micro/nano-structure and the end-facet of the optical fiber, then removing the end-facet of the optical fiber and the metallic micro/nano-structure from the surface of the substrate to complete the fabrication.

An application method of using an optical fiber having metallic micro/nano-structure on end-facet as a sensor, wherein the end-facet is an optical fiber end-facet basically perpendicular to the optical fiber, the metallic micro/nano-structure is a metallic micro/nano-structure resonance cavity, the metallic micro/nano-structure resonance cavity is formed by micro-nano patterns on a metallic film, the metallic micro/nano-structure resonance cavity makes the surface plasmon on the metallic film resonate, the metallic micro/nano-structure resonance cavity is aligned with a core layer of the optical fiber, and the optical fiber is a single-mode optical fiber and/or a bare optical fiber, and the method comprises the following steps:

• (1) contacting/moving the end-facet of the optical fiber that comprises the metallic micro/nano-structure resonance cavity with/towards a medium;
• (2) collecting reflected light obtained after light transmits along the optical fiber, reaches the end-facet of the optical fiber, and is reflected back to the optical fiber after surface plasmon resonance occurs in the metallic micro/nano-structure resonance cavity;
• and
• (3) analyzing a spectrum and/or a strength of the reflected light, and obtaining refractive index information of the medium according to a change of a wavelength and/or a luminous intensity of the surface plasmon resonance relative to a refractive index of the medium.