Kerr effect optimization in acetone-immersed optical nanofibers

Abstract

Nanoscale optical fibers, capable of confining light at the nanoscale, exhibit nonlinear effects and generate a strong evanescent field interacting with the surrounding environment. In this study, we compared various nanofibers composed of different glasses, closely matching the refractive index of silica, while immersed in acetone. Our objective was to optimize the Kerr effect contributions from either the core or the cladding, dependent on factors such as nanofiber dimensions, core optical properties, and the effective area of the fundamental mode HE[Formula: see text] both inside and outside the nanofiber core. Our findings reveal that the fluorophosphate (S-FPM3) nanofiber exhibits a dominant Kerr effect when immersed in acetone compared to the silica nanofiber. Specifically, for a radius [Formula: see text][Formula: see text]nm, the S-FPM3 nanofiber core demonstrates a Kerr coefficient [Formula: see text], three times higher than that of the silica nanofiber. Similarly, for [Formula: see text], the Kerr coefficient [Formula: see text] for the S-FPM3 nanofiber cladding is three times greater than that of the silica nanofiber, despite both having nearly identical nonlinear indices. Additionally, we observed that Kerr coefficients follow similar variations across different wavelengths in the visible and infrared regions, with values decreasing significantly due to the inverse proportionality with optical wavelength [Formula: see text]. Analyzing the dynamics of nanofiber normalized diameter reveals a sub-wavelength threshold optimizing effective nonlinearity, particularly in the case of the NC21A nanofiber. These findings suggest the potential use of optical nanofibers as reliable sensors in challenging-to-access areas for external media and the enhancement of nonlinear effects through the evanescent field.