3D chirality is shown to be unnecessary for introducing strong circular dichroism for harmonic generations. Specifically, near-unity circular dichroism for both second-harmonic generation and third-harmonic generations is demonstrated on suitably designed ultrathin plasmonic metasurfaces with only 2D planar chirality. The study opens up new routes for designing chip-type biosensing platform, which may allow for highly sensitive detection of bio- and chemical molecules with weak chirality.
Chen, S., Zeuner, F., Weismann, M., Reinike, B., Li, G., Valev, V. K., Cheah, K. W., Panoiu, N. C., Zentgraf, T., & Zhang, S. (2016). Giant nonlinear optical activity of achiral origin in planar metasurfaces with quadratic and cubic nonlinearities. Advanced Materials, 28(15), 2992-2999. https://doi.org/10.1002/adma.201505640