Replication Data for: Ge2Sb2Te5-Based Tunable Perfect Absorber Cavity with Phase Singularity at Visible Frequencies

The metal-dielectric stacks-based asymmetric Fabry-Perot (F-P) cavity systems have recently attracted much interest from the scientific community for realizing perfect absorption over the spectral bands from visible to infrared since they possess a lithography-free design that is cost-effective and scalable. Here, we experimentally demonstrate an asymmetric F-P cavity system for achieving tunable wide angle perfect absorption and phase singularity. The proposed system shows tunable multiband perfect absorption in the visible spectral region by incorporating an ultra-thin layer of phase change material such as Ge2Sb2Te5 (GST) in the stack. The system shows multi-narrowband perfect absorption with a maximum of 99.8% at a specific incident angle and polarization state when the GST is in amorphous phase, however, the absorption bands blue shift and broaden after switching to the crystalline phase. More importantly, the proposed scheme shows tunable phase singularity at the reflection-less point. The obtained tunable perfect absorption and abrupt phase change are solely due the presence of a highly absorbing ultra-thin layer of GST in the stack. Experimental results are validated using an analytical simulation model based on transfer matrix method. The proposed scheme could find potential active photonic device applications, especially for phase-sensitive biosensors and absorption filters.