Temperature-controlled tunable metamaterial absorber based on vanadium dioxide with "switch" functionality

Abstract The performance of traditional absorbers is fixed in a specific frequency or wavelength range, and the actual application often needs to adjust the absorption characteristics according to different scenarios or needs. A THz wave modulator, utilizing temperature-controlled phase change materials, is proposed to address the limitation of absorbers’ inability to adjust to external environments. Tunable absorber is a kind of device with dynamic regulation ability, and its absorption characteristics can be adjusted and optimized according to external conditions. This modulator enables the switch function of metamaterial absorbers, comprising a gold reflector layer, a silicon dioxide depletion layer, and a vanadium dioxide pattern layer. Simulations via finite element method reveal two nearly perfect absorption peaks, up to 99.99%. As temperature rises, absorption rates increase, stabilizing gradually after vanadium dioxide transitions from insulating to metallic phase. With a modulation depth of 98.49%, the absorber achieves adjustability. It enables polarization-independent absorption of electromagnetic waves, exhibiting strong absorption at incident angles from 0° to 50° for TE and TM waves. Leveraging vanadium dioxide’s phase change characteristics, the absorber can switch between ON and OFF states based on temperature changes, promising potential applications in light modulation and THz absorbers.