Spatiotemporal light control with frequency-gradient metasurfaces

Shaltout, Amr M. and Lagoudakis, Konstantinos G. and van de Groep, Jorik and Kim, Soo Jin and Vučković, Jelena and Shalaev, Vladimir M. and Brongersma, Mark L. (2019) Spatiotemporal light control with frequency-gradient metasurfaces. Science (New York, N.Y.), 365 (6451). pp. 374-377. ISSN 0036-8075 (

[thumbnail of Shaltout-etal-Science-2019-Spatiotemporal-light-control-with-frequency-gradient]
Text. Filename: Shaltout_etal_Science_2019_Spatiotemporal_light_control_with_frequency_gradient.pdf
Accepted Author Manuscript

Download (581kB)| Preview


The capability of on-chip wavefront modulation has the potential to revolutionize many optical device technologies. However, the realization of power-efficient phasegradient metasurfaces that offer full-phase modulation (0 to 2p) and high operation speeds remains elusive. We present an approach to continuously steer light that is based on creating a virtual frequency-gradient metasurface by combining a passive metasurface with an advanced frequency-comb source. Spatiotemporal redirection of light naturally occurs as optical phase-fronts reorient at a speed controlled by the frequency gradient across the virtual metasurface. An experimental realization of laser beam steering with a continuously changing steering angle is demonstrated with a single metasurface over an angle of 25° in just 8 picoseconds. This work can support integrated-on-chip solutions for spatiotemporal optical control, directly affecting emerging applications such as solid-state light detection and ranging (LIDAR), threedimensional imaging, and augmented or virtual systems.