Wide‐Angle Tunable Critical Coupling in Nanophotonic Optical Coatings with Low‐Loss Phase Change Material

Wide‐Angle Tunable Critical Coupling in Nanophotonic Optical Coatings with Low‐Loss Phase Change Material

Small

10.1002/smll.202202005

http://dx.doi.org/10.1002/smll.202202005

Kandammathe Valiyaveedu Sreekanth, Patinharekandy Prabhathan, Apoorva Chaturvedi, Yulia Lekina, Song Han, Shen Zexiang, Edwin Hang Tong Teo, Jinghua Teng, Ranjan Singh

General Materials Science, Biomaterials, General Chemistry, Biotechnology

17 June 2022

Sreekanth, K. V., Prabhathan, P., Chaturvedi, A., Lekina, Y., Han, S., Zexiang, S., Tong Teo, E. H., Teng, J., & Singh, R. (2022). Wide‐Angle Tunable Critical Coupling in Nanophotonic Optical Coatings with Low‐Loss Phase Change Material. Small, 18(28), 2202005. Portico. https://doi.org/10.1002/smll.202202005

Realizing perfect light absorption in stacked thin films of dielectrics and metals through critical light coupling has recently received intensive research attention. In addition, realizing ultrathin perfect absorber and tunable perfect absorber in the visible spectrum is essential for novel optoelectronics applications. However, the existing thin film stacks cannot show tunable perfect absorption in a wide-angle range. Here, we propose tunable perfect absorption from normal incidence to a wide-angle range (0º to 70o) by utilizing a two-layer stack consisting of a high refractive index low-loss dielectric on a high reflecting metal. We experimentally demonstrate this by depositing a thin layer of low-loss phase change material such as Sb2S3 on a thin layer of silver. This structure shows tunable perfect absorption with large spectral tunability in the visible wavelength. Furthermore, we demonstrate absorption enhancement in 2D materials by transferring monolayer MoS2 on the stack, which shows 96% light absorption with enhanced photoluminescence. In addition, the thin film stack can work as a scalable phase modulator offering a maximum phase tunability of ~140 o by changing the structural state of Sb2S3 from amorphous to crystalline.

Publisher Copyright

This research / project is supported by the A*STAR - HBMS Industry Alignment Fund - Pre-Positioning (IAF-PP)
Grant Reference no. : H19H6a0025

This research / project is supported by the A*STAR - AME Individual Research Grants
Grant Reference no. : A20E5c0084

This research / project is supported by the A*STAR - AME Individual Research Grants
Grant Reference no. : A2083c0058

This research / project is supported by the National Research Foundation - Competitive Research Programme
Grant Reference no. : CRF SC25/21-110318

This research / project is supported by the A*STAR - Advanced Manufacturing and Engineering (AME) Programmatic grant
Grant Reference no. : A18A5b0056

This is the peer reviewed version of the following article: Sreekanth, K. V., Prabhathan, P., Chaturvedi, A., Lekina, Y., Han, S., Zexiang, S., Tong Teo, E. H., Teng, J., & Singh, R. (2022). Wide‐Angle Tunable Critical Coupling in Nanophotonic Optical Coatings with Low‐Loss Phase Change Material. Small, 18(28), 2202005. Portico. https://doi.org/10.1002/smll.202202005, which has been published in final form at doi.org/10.1002/smll.202202005. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited.

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