In situ spectroelectrochemical ellipsometry using super continuum white laser: Study of the anodization of magnesium alloy

Abstract

This work shows the interest to use a real time white laser-based ellipsometer to characterize complex electrolyte | electrode interface during electrochemical process in aqueous-based medium. This method is proposed to probe electrochemical interfaces which are usually not suitable to the full extent application of ellipsometry due to great disturbance of the reflected light flux provoked by gas evolution or roughness. In situ spectroelectrochemical ellipsometry combining such a visible super continuum fiber laser-band source was not previously reported to the best of the authors' knowledge. The setup was employed to monitor an electrochemical process whose the mechanism was previously incompletely described: the pre-spark anodization regime of plasma electrolytic oxidation process of Mg alloy AZ91D in 3 M KOH electrolyte. Above the anodization voltage of 4 V, the side water oxidation reaction induced light diffusion that reduces reflected light beam intensity. The process is here monitored in an extended

High-power all-fiber supercontinuum generation in normal dispersion region

“…Supercontinuum (SC) generation in optical fibers shows substantial potential owing to the great directionality and broad spectral bandwidth. Numerous applications, including ultrahigh-resolution optical coherence tomography, [1] free-space broad-spectrum optical communication, [2] high-speed imaging, [3] spectroelectrochemical ellipsometry, [4] and spectral sensitivity evaluation, [5] are based on SC. Utilizing pulsed laser sources to inject into specialty optical fibers with a high nonlinear coefficient, such as photonic crystal fibers, [6,7] small-core tapered fibers, [8] fluorotellurite fibers, [9,10] has been proved to be a feasible and effective method for SC generation.…”