Study Of Spatial Light Manipulation Metasurface Based On Electro-Optic Materials

The control of space light is of great significance in the fields of high-speed information exchange,precise image processing,and sensitive detection.Optical metasurface is an artificially constructed two-dimensional surface with a sub-wavelength unit structure.Compared with traditional optical devices and systems,it has many advantages such as small size,easy processing,high-dimensional controllability,and sharp photo-material response.By constructing a special light field control metasurface structure,flexible control of spatial light amplitude,phase and polarization can be achieved.In order to realize intelligent and tunable optical functional devices,a large number of materials with excellent electro-optical control characteristics have been organically combined with optical metasurfaces,showing great potential in the application of spatial light dynamic control.However,the current metasurface design incorporating electro-optical materials also exhibits many shortcomings.In terms of amplitude control,bandwidth and modulation depth are lacking;in phase modulation,it is usually difficult to achieve continuous,smooth,and wide-range modulation performance;in terms of polarization control,no design for arbitrary polarization conversion has been proposed.In this paper,a variety of spatial light independent regulation of metasurface structure has been studied for the above problems,and the following progress has been made.Graphene,Molybdenum disulfide（Mo S₂）,Vanadium dioxide（VO₂）and Indium Tin Oxide（ITO）materials have excellent electro-optical properties,and there is a general lack of comprehensive and accurate simulations for them.Model.In order to more accurately model the above electro-optical materials,this article refers to and combines a large number of documents to improve the relevant parameters of the materials,and simulates through the finite element software Comsol Multiphysics to verify the correctness of the model.The study of space light control metasurface provides a theoretical basis.For the spatial light amplitude control supersurface,in order to achieve broadband and high-efficiency absorption of visible light,a broadband absorber based on the transition metal chalcogenide-metal nanoparticle structure is proposed,which achieves a wavelength higher than 400 nm-666 nm.90%efficient absorption.The proposed structure can be applied to the absorption enhancement of a variety of two-dimensional materials,providing a new realization method for applications such as photovoltaic devices and optical stealth.Existing amplitude modulators based on electro-optical materials still have the disadvantages of low modulation depth,complex structure,and high energy consumption.In order to achieve dynamic amplitude control,a variety of graphene-based spatial light amplitude modulators have been studied,including reflective and transmissive control mechanism to achieve low energy consumption and high modulation depth modulation performance.Among them,a modulation method combining graphene and artificial magnetic conductor（Artificial Magnetic Conductor,AMC）checkerboard cancellation structure is proposed for the first time,achieving a modulation depth higher than 32 d B.Finally,the transmissive amplitude modulation structure based on VO₂ was studied,and the performance indicators of the open state transmittance higher than 80%and the overall modulation depth higher than 74%were achieved.For spatial light phase control and beam dynamic control,a phase control structure based on graphene-based multi-resonance mechanism fusion is proposed.By analyzing the phase mutation mechanism and graphene control characteristics,a continuous smooth phase adjustment in a range is realized.The optical phased array and the adjustable focal length lens were successfully constructed using the phase modulation unit.Secondly,by analyzing the electro-optical characteristics of the ITO film,a phase modulation structure based on ITO-metal plasma resonance was studied,which achieved a phase modulation range higher than 330°.Finally,based on the phase distribution design,the light field distribution is adjusted to achieve an efficient transmissive beam splitting metasurface.By deriving the required transmission matrix,two-channel,four-channel,five-channel and eight-channel beam splitting structures are constructed respectively.Aiming at the conversion problem of arbitrary polarization,this paper proposes a metasurface design for arbitrary polarization conversion for the first time.For incident light of arbitrary polarization,it can be converted into a specific polarization.Combined with ordinary optical fiber,it can replace polarization-maintaining optical fiber for long-distance transmission of polarized light,which greatly saves costs.The designed super-surface has been processed and tested to achieve the effect of"first depolarization,then deflection".For the problem of cross polarization conversion,this paper studies the broadband（1.4μm-2.5μm）polarization control metasurface based on VO₂,and realizes the controllable switching of the main polarization and the cross polarization,which can be applied to the fields of optical communication and optical encryption.In summary,this article has conducted in-depth research on the amplitude,phase and polarization control technology of space light,and proposed a variety of control structures,which solves the problems of some existing space light modulation devices,and has broad application scenarios in the field of optoelectronics.