A four-state programmable mid-infrared band-stop filter exploiting a Ge₂Sb₂Te₅ film and VO₂ nanoparticles

We designed and demonstrated a four-state programmable mid-infrared band-stop absorber that exploits two different phase-change materials. This programmability is possible by exploiting Fabry–P erot resonances in a Ge2Sb2Te5 film and vanadium dioxide nanoparticles’ (VO2 NPs) dual layer. The reflectivity trough can be tuned to four different infrared (IR) wavelengths from 1906 to 2960nm by heating the structure to different temperatures. The near-perfect absorber is reconfigurable, lithography-free, industrially scalable, polarization-insensitive, and omnidirectional. Our strategy opens a path for programmable infrared photonics.Agency for Science, Technology and Research (A*STAR)Ministry of Education (MOE)National Research Foundation (NRF)Published versionThis work was supported by the National Research Foundation, Prime Minister’s Office, Singapore under its Campus for Research Excellence and Technological Enterprise (CREATE) program and Singapore Ministry of Education (MOE) Academic Research Fund Tier 1 RG103/19 and RG86/20. R.E.S. acknowledges support granted for the Nanospatial Light Modulators for Next-Gen Display Technologies (NSLM) project (A-Star AME Grant No. A18A7b0058)