Simulation of field-controlled electromagnetic resonance in terahertz metamaterials

The field-induced modulation of electromagnetic (EM) resonance in subwavelength metamaterial unit cells is theoretically analyzed. The external EM field interacts with free electrons undergoing resonant motion within subwavelength structures, resulting in a reduction of the EM resonance intensity of metamaterials while having minimal impact on their resonance wavelength. Full-wave EM simulations reveal that as the voltage increases from 0 to 9 V, the refractive index variation near the resonance wavelength reaches 0.6, with the modulation depths of the reflected and transmitted waves achieving 100% and 74%, respectively. In contrast to traditional resonance tuning techniques based on altering the optical properties of the ambient medium, this field-driven modulation strategy manipulates the dynamics of free electrons in the metamaterial, enabling high-speed terahertz modulators and facilitating a more compact device design.