Thermally Controllable Infrared Absorption in Cylindrical Groove Array Covered by Phase Change Material

Abstract

A perfect infrared spectrum absorber in a cylindrical groove array perforated in a metallic layer and followed by vanadium dioxide (VO2), a phase-change material, is introduced and analytically investigated. The phase-change material can change from insulator to metallic phase if proper stimuli, such as heat, voltage, and current, are applied, herein the phase change initiated by heating beyond the phase-transition temperature of VO2. The large refractive index variations between two phases enable the manipulation of optical properties. Simulation results reveal that in the metallic phase, the absorption is suppressed to one third, while VO2 works as a transparent medium for impinging light, and perfect absorption is observed in the insulation phase. The process is reversible in a picosecond time scale. Given the structure symmetry, the absorption is irreverent to impinging light polarization. The thermally controlled infrared absorber may have applications in various optical systems, like imaging and sensing, due to its simple and easy fabrication process.