石墨烯可调谐双频完美吸收器设计

Tunable Dual-Frequency Perfect Absorber with Graphene

利用石墨烯优异的可调光学特性,设计了一种由石墨烯谐振器、SiO 2介质层及金属反射层组成的可调谐双频完美吸收器,研究了石墨烯化学势、偏振角及尺寸大小对吸收器吸收性能的影响,并分析了共振频率处的电场模式,进一步解释吸收器的吸收原理.结果表明,吸收器在6.363 THz和8.987 THz处的吸收率分别为99.98%和99.99%;吸收峰位可通过改变石墨烯化学势进行有效调节,0°~80°范围内的任意偏振角下,峰值吸收率均可达90%以上;SiO 2介质层厚度对吸收器的共振峰位几乎没有影响,但对峰值吸收率有一定影响,随着厚度的逐渐增加,吸收率先升高后降低,在厚度为3.1μm附近时实现完美吸收.以上结果说明,吸收器的高吸收率主要源于电磁共振作用.

A tunable dual-frequency perfect absorber consisting of a graphene resonator,a SiO 2dielectric layer and a metal reflector layer has been designed by utilizing the excellent tunable optical properties of graphene.The effects of graphene chemical potential,polarization angle and size on the absorber absorption performance were systematically investigated,and the electric field pattern at the resonance frequency was analyzed to further explain the principle of absorber absorption.The results show that the absorber has an absorption rate of 99.98%and 99.99%at 6.363 and 8.987,respectively.The absorption peak position of the absorber can be effectively adjusted by changing the chemical potential of graphene,and the peak absorption rate can reach more than the peak absorption rate at any polarization angle in the range of 0°~80°.The thickness of the SiO 2 dielectric layer has almost no effect on the resonance peak position of this absorber,but it has some effect on the peak absorption rate,which increases and then decreases with the gradual increase of the thickness,and perfect absorption is achieved near the thickness of 3.1μm.The high absorption rate of this absorber stems mainly from the electromagnetic resonance effect.