Research Progress of Light-controlled Electromagnetic Metamaterials

Electromagnetic metamaterials are artificial structures composed of a periodic or aperiodic arrangement of subwavelength unit cells and can regulate the physical characteristics of electromagnetic waves, such as their frequency, amplitude, phase, and polarization. Metamaterials overcome many limitations of traditional materials and can be used to realize interesting physical phenomena and applications that do not occur in nature. Over the past two decades, metamaterials have become a focus in the fields of physics and electronics owing to their powerful electromagnetic regulation ability. However, passive metamaterials have limitations in electromagnetic wave regulation, such as fixed operating frequency and single function. As such, increasing attention is being paid to tunable and active metamaterials. By introducing active elements, the functions of metamaterials can be dynamically regulated by external excitation signals, which is highly significant for practical applications. At present, commonly used control methods include electrical, temperature, light, and mechanical controls, among which light control has the advantages of remote and noncontact control, a fast modulation speed, and a simple structure. In this study, we summarize the latest progress in light-controlled electromagnetic metamaterial research, and introduce recent work on light-controlled metamaterials and metasurfaces in direct currents, microwaves, terahertz waves, and optics. We focus primarily on relevant operational mechanisms and application scenarios and discuss future prospects.