Fabrication and characterization of optical micro/nanofibers

We experimentally demonstrate the fabrication of optical micro/nanofibers (MNFs) using chemical etching and gas-flame techniques. In the chemical etching technique, a two-step process involves 40% and 24% of hydrofluoric acid solutions for the first and second steps, respectively. The measured diameters of MNFs range is 0.34 $\mu$m - 1.4 $\mu$m. In the gas-flame technique, we design the pulling parameters in a four-step process to achieve the desired diameter of MNFs. The single-mode fiber is adiabatically tapered using high-precision stages while heating the fiber with hydrogen-oxygen flame. The measured diameters of pulled MNFs range is 0.48 $\mu$m - 0.53 $\mu$m, showing good correspondence with the designed diameters. Due to the strong confinement of the field around the MNF, it has diverse applications in various fields, such as sensing, nanophotonics, quantum optics, quantum photonics, and nonlinear optics.