Research On Metamaterials In Electromagnetic Wave Contro

Metamaterials is artificial materials composed of subwavelength periodic units,which can realize some special electromagnetic response properties which natural materials haven’t.The special electromagnetic response properties of metamaterials and their inherent physical mechanisms have attracted attention.With the help of metamaterials,effective modulation of light field such as amplitude,phase and polarization of light can be realized at the nanometer scale.In this paper,we mainly focuses on the physical mechanism,regulation means and structural design of light field regulation by metamaterials.The polarization conversion metamaterial,perfect absorber metamaterial and plasmon-induced transparency metamaterial are designed.The proposed structures are modeled and simulated by finite element method,and the effects of electromagnetic modulation and its internal physical mechanisms are discussed through the corresponding spectral curve and field intensity distribution.The main contents are as follows:(1)The concept and properties of metamaterials,calculation methods and research status are briefly introduced.Two types of dynamically tunable metamaterials are discussed in detail.(2)Based on the phase transition properties of vanadium dioxide,a broadband efficient reflective linear-to-circular(LTC)polarization converter controlled by temperature is proposed.The principles of polarization conversion and dynamic tuning are explored by studying normalized ellipticity,phase difference and electric field distribution.The final results show that the normalized ellipticity is almost 1 in the wavelength range of 430-650 nm,and the polarization converter can be switched "on/off" by the conductivity of vanadium dioxide.The polarization converter has potential applications in sensing and optical communication.(3)A dual narrowband polarization-insensitive metamaterial perfect absorber with silicon nanodisk,dielectric layer,and gold film structure is proposed for communication wavelengths.The absorber has two resonance peaks with 99% absorption at 1310 nm and1550 nm.The physical mechanism of the resonance absorption peaks is explored by the absorption spectra and electric field distributions,as well as the effects of structural parameters on the dual absorption peaks are analyzed.And the effects of the angle of incidence and the angle of polarization of the incident light on the absorption spectra are discussed.The absorber has potential applications in communications.(4)Based on graphene plasmon,a plasmon-induced transparency metamaterial consisting of silicon and symmetric graphene ellipsoidal disk arrays is designed.The physical mechanism of transmission window is elaborated by analyzing its transmission spectrum,electric field distribution at resonance wavelength.The effects of the structural parameters,Fermi energy level of graphene on PIT are analyzed.The applications in optical switching,sensing and slow light are discussed theoretically.