Research on the polymeric Fiber-Tip Fabry-Perot cavity with high reflective mirror manufactured by the Two-Photon Polymerization method

In this study, we present a fiber-tip Fabry-Perot interferometer operating in reflective mode, fabricated on the end faces of standard single-mode optical fibers using the Two-Photon Polymerization 3D nanoprinting method. Theoretical analysis highlights the primary challenge in accurately fitting the geometric dimensions of the cavity due to light beam divergence at the end of a single-mode fiber. Therefore, significant emphasis was placed on creating a compact structure with a high-reflection mirror formed on the printed tip. Various shapes of reflective surfaces were tested, including flat and concave. Additionally, to improve reflection we used the cathode sputtering method to get thin metal films on the printed surfaces. During conducted research, it has been demonstrated that the optimal solution is to cover only one surface of the resonator. This necessitated the development of a structure with a unique shape, enabling the deposition of a thin metallic layer solely on the top surface while simultaneously preventing deposition on the core.