Probing Graphene χ(2) Using a Gold Photon Sieve

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• 作者：Micha?l Lobet ; Micha?l Sarrazin ; Francesca Cecchet ; Nicolas Reckinger ; Alexandru Vlad ; Jean-Fran?ois Colomer ; Dan Lis
• 刊名：Nano Letters
• 出版年：2016
• 出版时间：January 13, 2016
• 年：2016
• 卷：16
• 期：1
• 页码：48-54
• 全文大小：512K
• ISSN：1530-6992

文摘

Nonlinear second harmonic optical activity of graphene covering a gold photon sieve was determined for different polarizations. The photon sieve consists of a subwavelength gold nanohole array placed on glass. It combines the benefits of efficient light trapping and surface plasmon propagation to unravel different elements of graphene second-order susceptibility χ⁽²⁾. Those elements efficiently contribute to second harmonic generation. In fact, the graphene-coated photon sieve produces a second harmonic intensity at least two orders of magnitude higher compared with a bare, flat gold layer and an order of magnitude coming from the plasmonic effect of the photon sieve; the remaining enhancement arises from the graphene layer itself. The measured second harmonic generation yield, supplemented by semianalytical computations, provides an original method to constrain the graphene χ⁽²⁾ elements. The values obtained are |d₃₁ + d₃₃| ≤ 8.1 × 10³ pm²/V and |d₁₅| ≤ 1.4 × 10⁶ pm²/V for a second harmonic signal at 780 nm. This original method can be applied to any kind of 2D materials covering such a plasmonic structure.