Large optical nonlinearity of nanoantennas coupled to an epsilon-near-zero material
Abstract
The size and operating energy of a nonlinear optical device are fundamentally constrained by the weakness of the nonlinear optical response of common materials1. Here, we report that a 50-nm-thick optical metasurface made of optical dipole antennas coupled to an epsilon-near-zero material exhibits a broadband (∼400 nm bandwidth) and ultrafast (recovery time less than 1 ps) intensity-dependent refractive index n2 as large as −3.73 ± 0.56 cm2 GW−1. Furthermore, the metasurface exhibits a maximum optically induced refractive index change of ±2.5 over a spectral range of ∼200 nm. The inclusion of low-Q nanoantennas on an epsilon-near-zero thin film not only allows the design of a metasurface with an unprecedentedly large nonlinear optical response, but also offers the flexibility to tailor the sign of the response. Our technique removes a longstanding obstacle in nonlinear optics: the lack of materials with an ultrafast nonlinear contribution to refractive index on the order of unity. It consequently offers the possibility to design low-power nonlinear nano-optical devices with orders-of-magnitude smaller footprints.
Citation
Alam , M Z , Schulz , S A , Upham , J , De Leon , I & Boyd , R W 2018 , ' Large optical nonlinearity of nanoantennas coupled to an epsilon-near-zero material ' , Nature Photonics , vol. 12 , no. 2 , pp. 79-83 . https://doi.org/10.1038/s41566-017-0089-9
Publication
Nature Photonics
Status
Peer reviewed
ISSN
1749-4885Type
Journal article
Rights
© 2018, the Author(s). This work has been made available online in accordance with the publisher’s policies. This is the author created, accepted version manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at https://doi.org/10.1038/s41566-017-0089-9
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