Fig. 3.

Temporal modulation of the metasurface. a Switching performance of the metasurface at different frequencies. The starting frequency is 0.25 Hz, reaching 100 Hz in 20 seconds on a logarithmic increment. Then the system operates with a 100 Hz switching time for 2 seconds and reverts to the 0.25 Hz in 20 seconds by a logarithmic decrement. The modulation performance of the metasurface is shown in the bottom plots at the frequency of 1 Hz (green), 30 Hz (yellow) and 100 Hz (pink). b Switching performance of the system at different bias voltages. c Lower and upper boundaries of the metasurface transmission intensity across the frequency sweep at different voltage biases. Optical images are taken from the metasurface d at room temperature and e when it is heated to 200 °C. The SEM image on the right-hand side shows the silicon membrane