Imaging collective behavior in an rf-SQUID metamaterial tuned by DC and RF magnetic fields

Alexander P. Zhuravel; Seokjin Bae; Alexander V. Lukashenko; Alexander S. Averkin; Alexey V. Ustinov; Steven M. Anlage

doi:10.1063/1.5064658

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arXiv · 1811.11261

Imaging collective behavior in an rf-SQUID metamaterial tuned by DC and RF magnetic fields

Alexander P. Zhuravel·Seokjin Bae·Alexander V. Lukashenko·Alexander S. Averkin·Alexey V. Ustinov·Steven M. Anlage

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Abstract

We examine the collective behavior of two-dimensional nonlinear superconducting metamaterials using a non-contact spatially resolved imaging technique. The metamaterial is made up of sub-wavelength nonlinear oscillators in a strongly coupled 27x27 planar array of radio-frequency Superconducting QUantum Interference Devices (rf SQUIDs). By using low-temperature laser scanning microscopy we image microwave currents in the driven SQUIDs while in non-radiating dark modes and identify the clustering and uniformity of like-oscillating meta-atoms. We follow the rearrangement of coherent patterns due to meta-atom resonant frequency tuning as a function of external dc and rf magnetic flux bias. We find that the rf current distribution across the SQUID array at zero dc flux and small rf flux reveals a low degree of coherence. By contrast, the spatial coherence improves dramatically upon increasing of rf flux amplitude, in agreement with simulation.

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Alexander P. Zhuravel, Seokjin Bae, Alexander V. Lukashenko, Alexander S. Averkin, Alexey V. Ustinov, Steven M. Anlage. 2019-01-15. Imaging collective behavior in an rf-SQUID metamaterial tuned by DC and RF magnetic fields. https://doi.org/10.1063/1.5064658

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