Investigation Of The Dynamically Tunable Spectral Engineering With Subwavelength Structures

Subwavelength structures exhibit salient advantages in terms of controlling and manipulating light-matter interactions at subwavelength scale due to their exotic electromagnetic properties,which are of particular importance in the electromagnetic and optical areas.Unlike traditional composite or natural materials,the electromagnetic properties of subwavelength structures do not only depend on its structural composition,but also the morphology and arrangement of different components.Most importantly,tailoring the parameters of subwavelength structures provides an efficient mean for spectral engineering,phase manipulation,polarization control,and many more.It,therefore,reaps significant benefits for achieving tunable spectra,controllable polarization,etc.However,the spectra will be also stuck in the fixed morphological nanostructure.With respect to the limitation,integrating or embedding the materials or structures with tunable optical properties could be a better approach to overcome the bottleneck.Consequently,benefiting from these advantageous strategies,actively tunable structural color rendering device,multiband polarization manipulation antennas and multifunctional devices have been achieved.The main original work of this dissertation includes the following parts:1.To investigate the dynamically tunable structure colors,one of the tensile materials is introduced into the subwavelength structures,i.e.,metasurfaces,to propose a new method to realize the tunable colors.With the external force on PDMS substrate,deformation occurs.Therefore,the period of the metasurface will change correspondingly,which experimentally indicates the color varying from green to fuchsia.2.The strategies for changing colors,possessing both reversible dynamic response and distinct optical behavior,are naturally single-function,which means that these structures or devices will only work in the visible spectral range as color filtering,color printing,sensing and so on.The broadband multifunctional properties has been realized by introducing vanadium dioxide into metamaterial absorber.Through the modified design and high efficient utilization of multiple resonant modes,both plasmonic tunable color filters and near-infrared photodetectors can be simultaneously achieved by this construction.Meanwhile,active color and photodetection wavelength in near infrared range can become tunable with the insulator-metallic transition of vanadium dioxide.Thus,the variations of rendering colors could correspondingly indicate the shifts of near-infrared photodetection bands.3.Based on the optical storage mechanism and electromagnetic properties of Ge₂Sb₂Te₅,we expand the applications of Ge₂Sb₂Te₅ from optical storage into the tunable spectra by utilizing Ge₂Sb₂Te₅ based metamaterial absorber.The dynamic color display and near-infrared light modulation can be simultaneously achieved in measurements,and the rendering colors can represent the near-infrared light modulation state.4.In order to satisfy the requirement the multiband and multiple polarization manipulation,we propose an approach to establish polarization reconfigurable chiral metamaterial based on asymmetric planar spirals by introducing vanadium dioxide in the unit cells.The polarization of the transmitted electromagnetic wave can be switched between the left-handed and right-handed circular polarizations with the insulator-metal transition of vanadium dioxide.This method holds great promise for future versatile utilization of multiband and multiple circularly polarized antenna systems.