Giant two-photon absorption in bilayer graphene
Yang, H. Feng, X. Wang, Q. Huang, H. Chen, W. Wee, A.T.S. Ji, W.
Yang, H.
Wang, Q.
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Abstract
We present a quantum perturbation theory on two-photon absorption (2PA) in monolayer and bilayer graphene which is Bernal-stacked. The theory shows that 2PA is significantly greater in bilayer graphene than monolayer graphene in the visible and infrared spectrum (up to 3 μm) with a resonant 2PA coefficient of up to ∼0.2 cm/W located at half of the bandgap energy, γ1 = 0.4 eV. In the visible and terahertz region, 2PA exhibits a light frequency dependence of ω-3 in bilayer graphene, while it is proportional to ω-4 for monolayer graphene at all photon energies. Within the same order of magnitude, the 2PA theory is in agreement with our Z-scan measurements on high-quality epitaxial bilayer graphene deposited on SiC substrate at light wavelength of 780 and 1100 nm. © 2011 American Chemical Society.
Keywords
ballistic photocurrent, Bilayer graphene, second-order perturbation thoery, two-photon absorption, Z-scan
Source Title
Nano Letters
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Series/Report No.
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Date
2011-07-13
DOI
10.1021/nl200587h
Type
Article