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Title: Ge2Sb2Te5 - based tunable perfect absorber cavity with phase singularity at visible frequencies
Authors: Sreekanth, Kandammathe Valiyaveedu
Han, Song
Singh, Ranjan
Keywords: DRNTU::Science::Physics
Perfect Absorbers
Issue Date: 2018
Source: Sreekanth, K. V., Han, S., & Singh, R. (2018). Ge2Sb2Te5 - based tunable perfect absorber cavity with phase singularity at visible frequencies. Advanced Materials, 30(21), 1706696-. doi:10.1002/adma.201706696
Series/Report no.: Advanced Materials
Abstract: 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. This study experimentally demonstrates 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 ultrathin 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 blueshift 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 to the presence of a highly absorbing ultrathin layer of GST in the stack. Experimental results are validated using an analytical simulation model based on a transfer matrix method. The proposed scheme could find potential applications in active photonic devices such as phase‐sensitive biosensors and absorption filters.
ISSN: 0935-9648
Rights: © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. This is the peer reviewed version of the following article: Sreekanth, K. V., Han, S., & Singh, R. (2018). Ge2Sb2Te5-Based Tunable Perfect Absorber Cavity with Phase Singularity at Visible Frequencies. Advanced Materials, 30(21), 1706696-, which has been published in final form at This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.
Fulltext Permission: open
Fulltext Availability: With Fulltext
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