Programmable Terahertz Metamaterials with Non‐Volatile Memory

Abstract

Spatial light modulators (SLMs) exhibited the powerful capability of controlling the electromagnetic wave. They have found numerous applications at terahertz (THz) frequencies, including wireless communication, digital holography, and compressive imaging. However, the development towards largescale, multi-level and multi-functional THz SLM encounters technical challenges. Here, we present an electrically programmable THz metamaterial consisting of an array of 8⊆8 pixels, in which the phase change material of vanadium dioxide (VO 2 ) is embedded. After successfully suppressing the crosstalk from adjacent pixels, the THz wave could be modulated in a programmable manner. The switching speed of each pixel was on the order of 1 kHz. In particular, utilising the hysteresis effect of VO 2 , 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 could be generated and stored, with a retention time of more than 5 hours. This programmable metamaterial with memory effect can be extended to other frequency bands and opens a route for electromagnetic information processing.

Terahertz Reconfigurable Intelligent Surfaces (RISs) for 6G Communication Links

“…Recently, an electrically triggered VO 2 -based reconfigurable metasurface for both phase (90 • ) and amplitude (71% at 0.79 THz) modulation was experimentally demonstrated in [96]. And a multi-state 8 × 8 pixelated reflective modulator was demonstrated with a modulation speed of 1 kHz [97].…”

Programmable VO2 metasurface for terahertz wave beam steering

“…While, we cannot conduct the device fabrications and performance measurement due to the lack of experimental conditions. Based on the previous work ( Shabanpour et al., 2020 ; Chen et al., 2022 ), the meta-atom structures can be possibly fabricated as follows: First, a layer of VO 2 (0.2 μm thick) is deposited on the quartz substrate (500 μm thick) by reactive magnetron sputtering. Next, the pattern of VO 2 patch is formed by the lithography and reactive ion etching.…”

“…Therefore, it is still challenging to realize real time controlling the wide deflection angle of THz beam. Programmable metasurfaces have been demonstrated to be suitable for real-time control of electromagnetic wave ( Ghorbani et al., 2021 ; Shabanpour et al., 2021a ; Chen et al., 2022 ). Vanadium dioxide (VO 2 ) is a reversible phase-transition material triggered by thermal, optical, or electrical excitations, and it has advantages of the fast response and large modulation depth ( Huang et al., 2020 ).…”

Recent Progress of Terahertz Spatial Light Modulators: Materials, Principles and Applications

“…Recently, Jin et al proposed a nonvolatile VO 2 programmable metasurface based on the hysteresis feature [ 78 ]. It consists of 8 × 8 pixels with each pixel composed of VO 2 and the bowtie-shaped metallic structure.…”