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arXiv · 2307.11626

Sol-gel Barium Titanate Nanohole Array as a Nonlinear Metasurface and a Photonic Crystal

Ülle-Linda Talts·Helena C. Weigand·Grégoire Saerens·Peter Benedek·Joel Winiger·Vanessa Wood·Jürg Leuthold·Viola Vogler-Neuling·Rachel Grange
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Abstract

The quest of a nonlinear optical material that can be easily nanostructured over a large surface area is still ongoing. Here, we demonstrate a nanoimprinted nonlinear barium titanate 2D nanohole array that shows optical properties of a 2D photonic crystal and metasurface, depending on the direction of the optical axis. The challenge of nanostructuring the inert metal-oxide is resolved by direct soft nanoimprint lithography with sol-gel derived barium titanate enabling critical dimensions of 120 nm with aspect ratios of 5. The nanohole array exhibits a photonic bandgap in the infrared range when probed along the slab axis while lattice resonant states are observed in out-of-plane transmission configuration. The enhanced light-matter interaction from the resonant structure enables to increase the second-harmonic generation in the near-UV by a factor of 18 illustrating the potential in the flexible fabrication technique for barium titanate photonic devices.

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Ülle-Linda Talts, Helena C. Weigand, Grégoire Saerens, Peter Benedek, Joel Winiger, Vanessa Wood, Jürg Leuthold, Viola Vogler-Neuling, Rachel Grange. 2023-07-21. Sol-gel Barium Titanate Nanohole Array as a Nonlinear Metasurface and a Photonic Crystal. https://arxiv.org/abs/2307.11626

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