Programmable Terahertz Metamaterials with Non-Volatile Memory

Spatial light modulators (SLMs) exhibit a powerful capability of controlling electromagnetic waves. They are found to have numerous applications at terahertz (THz) frequencies, including wireless communication, digital holography, and compressive imaging. However, the development toward large-scale, multi-level, and multi-functional THz SLM encounters technical challenges. Here, an electrically programmable THz metamaterial consisting of an array of 8x8 pixels is presented, in which the phase change material of vanadium dioxide (VO2) is embedded. After successfully suppressing the crosstalk from adjacent pixels, the THz wave can be modulated in a programmable manner. The switching speed of each pixel is in the order of 1 kHz. In particular, utilizing the hysteresis effect of VO2, the memory effect is demonstrated. The THz amplitude of each pixel can be written and erased by individual current pulses. Furthermore, multi-state THz images can be generated and stored. This programmable metamaterial with memory function can be extended to other frequency bands and opens a route for electromagnetic information processing.