Fig. 3: Working principle and performance of the 4-bit DMSD.

a Schematic of the electrically-controlled DMSD. An array of gold nanorods spaced by PC403 resides on a gold electrode. All nanorods are embedded in another PC403 layer of 50 nm. The alternating columns are then either covered by high-birefringence LCs (n_a) or by a PMMA (n_b) trench of thickness t. Δφ_p is finely tuned, when n_a is dynamically changed upon electric control of the LCs and n_b is fixed. n_o and n_e are the ordinary and extraordinary refractive indices of the LCs, respectively. The incident light (633 nm) is linearly polarized along the PMMA trenches. b SEM image of the DMSD. Four addressable metasurface pixels (M1–M4) are controlled via four independent gold electrodes. Inset: enlarged SEM image of the gold nanorods in two neighboring columns covered by n_a and n_b, respectively. c Programmable optical information (“1111”, “0111”, etc.) is dynamically generated by the 4-bit DMSD. d Intensity of the anomalously reflected light as a function of the applied voltage V. An intensity modulation ratio as large as 105:1 is achieved. e Cycling performance of the DMSD, demonstrating excellent reversibility.