Optically Reconfigurable Photonic Devices

TL;DR

This paper introduces a novel dielectric metasurface platform that enables non-volatile, reversible optical reconfiguration using femtosecond laser pulses to induce phase changes in a nanoscale film, allowing dynamic control of optical devices.

Contribution

The work presents a new method for creating reconfigurable optical components via light-induced phase transitions in a dielectric film, advancing beyond mechanical or thermal tuning techniques.

Findings

Demonstrated reconfigurable Fresnel zone-plates in the visible range

Created a super-oscillatory lens with sub-wavelength focus

Developed grey-scale holograms and tunable metamaterials

Abstract

Optoelectronic components with adjustable parameters, from variable-focal-length lenses to spectral filters that can change functionality upon stimulation, have enormous technological importance. Tuning of such components is conventionally achieved by either micro- or nano-mechanical actuation of their consitutive parts, stretching or application of thermal stimuli. Here we report a new dielectric metasurface platform for reconfigurable optical components that are created with light in a non-volatile and reversible fashion. Such components are written, erased and re-written as two-dimensional binary or grey-scale patterns into a nanoscale film of phase change material by inducing a refractive-index-changing phase-transition with tailored trains of femtosecond pulses. We combine germanium-antimony-tellurium-based films optimized for high-optical-contrast ovonic switching with a sub-wavelength-resolution optical writing process to demonstrate technologically relevant devices: visible-range reconfigurable bi-chromatic and multi-focus Fresnel zone-plates, a super-oscillatory lens with sub-wavelength focus, a grey-scale hologram and a dielectric metamaterial with on-demand reflcetion and transmission resonances.