Ultrafast Spectroscopy of Graphene-Protected Thin Copper Films
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- 作者：Eva A. A. Pogna ; Stefano Dal Conte ; Giancarlo Soavi ; Vasyl G. Kravets ; Yong-Jin Kim ; Stefano Longhi ; Alexander N. Grigorenko ; Giulio Cerullo ; Giuseppe Della Valle
- 刊名：ACS Photonics
- 出版年：2016
- 出版时间：August 17, 2016
- 年：2016
- 卷：3
- 期：8
- 页码：1508-1516
- 全文大小：600K
- 年卷期：0
- ISSN：2330-4022
文摘
We studied by broad-band pump–probe spectroscopy the ultrafast optical response of thin copper films covered by a monolayer of graphene. It is demonstrated that graphene protection does not alter the thermo-modulational nonlinearity of copper in the whole visible range. Also, we provide a quantitative validation of a theoretical model for this optical nonlinearity, derived from a semiclassical description of electron thermalization dynamics and subsequent modulation of copper dielectric function from 450 to 700 nm wavelength. Our results extend to the nonlinear domain the capability of graphene-protected copper nanolayers to serve as a low cost optical grade material, with major potential impact on nonlinear plasmonics and metamaterials.