Measuring linear and nonlinear metasurfaces using Hilbert transforms
Metasurfaces based on epsilon-near-zero materials show very strong nonlinear responses and allow coupling of light to optical modes in the epsilon-near-zero thin film that are otherwise not accessible at normal incidence. However, measuring the phase shift due to these metasurfaces can be extremely challenging. Together with the Synthetic Optics group here in St Andrews, we have now demonstrated that simple transmission measurements, followed by an analysis based on Hilbert transform are sufficient to extratct the linear and nonlinear behaviour of these metasurfaces.
The approach can be applied to both simulated and experimental data and is therefore suitable foir predicting the nonlinear response of a metasurface.
Particular mentions here to my PhD student Laura Wynne and Hamish Balantyne, who was with us as a summer project student. For both of whom this represents their first publication.
The full article is published in “Photonics and Nanostructures: Fundamentals and Applications”.