Fabrication method of metal nanostructure and fiber-optic localized surface plasmon resonance sensor

A method of fabricating a metal nanostructure, the method comprising:

• attaching metal nanoparticles to a surface of an optical fiber treated with a first surface modifier by dipping the surface of the optical fiber into a metal solution;
• forming a metal nanostructure by annealing the metal nanoparticles attached to the surface of the optical fiber;
• removing the first surface modifier existing on the surface of the optical fiber after the metal nanostructure is formed, through chemical treatment and/or physical treatment;
• treating the metal nanostructure formed on the surface of the optical fiber with a second surface modifier;
• attaching additional metal nanoparticles to the metal nanostructure treated with the second surface modifier by dipping the metal nanostructure into the metal solution;
• and
• increasing a size of the metal nanostructure by annealing the additional metal nanoparticles attached to the metal nanostructure.

A fiber-optic localized surface plasmon resonance (FO LSPR) sensor comprising:

• an optical fiber;
• and
• a multi-nanogap structure formed on a surface of the optical fiber,
• wherein the multi-nanogap structure is formed by attaching metal nanoparticles having a first size to a surface of an optical fiber treated with a first surface modifier by dipping the surface of the optical fiber into a first metal solution, forming a metal nanostructure by annealing the metal nanoparticles having the first size attached to the surface of the optical fiber, removing the first surface modifier existing on the surface of the optical fiber after the metal nanostructure is formed, through chemical treatment and/or physical treatment, treating the metal nanostructure formed on the surface of the optical fiber with a second surface modifier, and dipping the metal nanostructure treated with the second surface modifier into a second metal solution and attaching metal nanoparticles having a second size to the metal nanostructure.