基于二氧化钒的可见光超材料饱和吸收体

Visible Light Metamaterial Saturable Absorber Based on Vanadium Dioxide

超材料吸波体凭借其可以在特定波长处实现接近100%的“完美”吸收而被广泛应用在各个领域中。具有可饱和吸收特性的超材料可以用来调控激光脉冲,但超材料光学性质的研究主要集中于红外或太赫兹波段,可见光波段研究较少。基于传统的超材料吸波体三层结构模型,借助二氧化钒的电磁参数随温度变化的相变特性,设计了一种实用的可见光波段超材料饱和吸收体。该超材料的吸收率会随着入射电磁波引起的温度升高而饱和,最终其会转变为高反射状态,具有类似半导体饱和吸收镜的特性。对该结构进行数值模拟,发现其在405~650 nm波长范围内,平均饱和深度为16%。

Metamaterial absorbers are widely used in various fields due to their ability to achieve"perfect"absorption close to 100%at a specific wavelength.Metamaterials with saturable absorption properties can be used to control laser pulses,but the studies on the optical properties of metamaterials are mainly focused on infrared or terahertz bands,and there are few studies in visible bands.Based on the traditional three-layer structure model of the metamaterial absorber and the phase change characteristics of the vanadium dioxide which has the temperature-dependent electromagnetic parameters,a visible range metamaterial saturable absorber is designed.The absorptivity of this kind of absorber will be saturated with the increase of the temperature caused by the incident electromagnetic wave,and finally it will convert to a highly reflective state,which is similar to that of a semiconductor saturable absorber mirror.The numerical simulation of the structure shows that the average saturation depth is 16%in the wavelength range of 405-650 nm.