Terahertz Tunable Metamaterial Absorber

The absorber made by using metamaterials has the advantages of better terahertz absorption efficiency,small thickness of the dielectric layer of the created model,light overall weight,and controllable absorption performance.It can accomplish high retention of electromagnetic waves with idealized absorption retention,dual-band,multi-band,and wide-band to suit various needs,so it is widely used in imaging,high-performance detection,solar cells,and stealth technology.In this dissertation multi-band and broadband absorbers composed of photosensitive silicon,graphene,and VO₂are investigated by optimizing the structural size design,respectively,and several aspects are discussed in depth.The main research contents are as follows.1.First of all,a photosensitive silicon multiband absorber was designed by adding a photosensitive silicon dielectric in the top metal layer,and the proposed metamaterial absorber obtained two perfect absorption rates at 2.67 THz and 4 THz when there was no light in the frequency range of 0～5 THz,which were 99.60%and99.79%,respectively.By changing different polarization modes such as TEM,TE,and TM and increasing the incident angle,the designed absorber frequency is transformed from dual-band perfect absorption to multi-band absorption,which can be applied in a wider range of applications in a larger scenario.2.Secondly,based on graphene and alum,a THz metamaterial absorber with three types of phase transitions:single-band,dual-band,and wideband were constructed.The variety of absorption bands can be accomplished by changing the Fermi energy level of graphene and the stage move of VO₂.single-band absorbers with distinctive frequencies can be gotten when VO₂is within the metallic state.By making VO₂transition from metallic to insulated,a dual-band absorber can be obtained.When VO₂is within the metallic state,the retention transmission capacity is extended by the common coupling of graphene with it,and broadband absorption is accomplished.Compared with the as of now existing absorbers,our outlined absorber based on graphene and VO_2,not as it were gives higher transmission capacity,but moreover has higher integration,is extremely compatible,and has a more extensive adaptability alteration run.