Photonics Research, 2016, 4 (4): 04000146, Published Online: Sep. 29, 2016
Visible-near infrared ultra-broadband polarization-independent metamaterial perfect absorber involving phase-change materials Download: 1451次
Metamaterials Metamaterials Photothermal effects Photothermal effects Surface plasmons Surface plasmons Microcavities Microcavities Absorption Absorption Ultrafast devices Ultrafast devices
Abstract
We numerically demonstrate a novel ultra-broadband polarization-independent metamaterial perfect absorber in the visible and near-infrared region involving the phase-change material Ge2Sb2Te5 (GST). The novel perfect absorber scheme consists of an array of high-index strong-absorbance GST square resonators separated from a continuous Au substrate by a low-index lossless dielectric layer (silica) and a high-index GST planar cavity. Three absorption peaks with the maximal absorbance up to 99.94% are achieved, owing to the excitation of plasmon-like dipolar or quadrupole resonances from the high-index GST resonators and cavity resonances generated by the GST planar cavity. The intensities and positions of the absorption peaks show strong dependence on structural parameters. A heat transfer model is used to investigate the temporal variation of temperature within the GST region. The results show that the temperature of amorphous GST can reach up to 433 K of the phase transition temperature from room temperature in just 0.37 ns with a relatively low incident light intensity of 1.11 × 108 W∕m2, due to the enhanced ultra-broadband light absorbance through strong plasmon resonances and cavity resonance in the absorber. The study suggests a feasible means to lower the power requirements for photonic devices based on a thermal phase change via engineering ultra-broadband light absorbers.
Ximin Tian, Zhi-Yuan Li. Visible-near infrared ultra-broadband polarization-independent metamaterial perfect absorber involving phase-change materials[J]. Photonics Research, 2016, 4(4): 04000146.