The design of practicable phase-change metadevices for near-infrared absorber and modulator applications
Santiago García-Cuevas Carrillo
Geoffrey R. Nash
Martin J. Cryan
Optical Society of America
Phase-change chalcogenide alloys, such as Ge2Sb2Te5 (GST), have very different optical properties in their amorphous and crystalline phases. The fact that such alloys can be switched, optically or electrically, between such phases rapidly and repeatedly means that they have much potential for applications as tunable photonic devices. Here we incorporate chalcogenide phase-change films into a metal-dielectric-metal metamaterial electromagnetic absorber structure and design absorbers and modulators for operation at technologically important near-infrared wavelengths, specifically 1550 nm. Our design not only exhibits excellent performance (e.g. a modulation depth of ~ 77% and an extinction ratio of ~ 20 dB) but also includes a suitable means for protecting the GST layer from environmental oxidation and is well-suited, as confirmed by electro-thermal and phase-transformation simulations, to in-situ electrical switching. We also present a systematic study of design optimization, including the effects of expected manufacturing tolerances on device performance and, by means of a sensitivity analysis, identify the most critical design parameters
We acknowledge gratefully the funding provided by the UK Engineering and Physical Sciences Research Council (EPSRC) grant number EP/K020196/1.
This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.
Vol. 23, Issue 10, pp. 13443-13454 (2015)