The Study Of Beam Splitter Based On Metasurfeaces

Light modulation has always been of great academic and practical value in the filed communication,imaging,radiation and other applications.Metasurfaces,twodimensional metamaterials,has attracted great attention with high integration since its emergence.Metasurfaces can modulate the phase,amplitude and polarization of light in subwavelength scale.The appearance of generalized scattering law makes the design of metasurfaces flexible.Since the concept of metasurfaces was first proposed by Nanfang Yu and co-workers in 2011,high-efficiency reflect-array and transmit-array metasurfaces have been proposed and verified by experiments.The remarkable feature of the reflectarray metasurface is that the bottom layer of the structure is a thick metal layer.And transmit-array metasurfaces are characterized by the structure only composed of lossless dielectric materials and no metal materials.Planar optical devices,such as planar lens,quarter wave plate and optical deflector,have been realized in the subwavelength scale by the optical modulation capability of metasurfaces.In this paper,the progress of optical frequency metasurfaces is reviewed in detail,and the design methods and applications of metasurfaces are described.Based on the generalized laws of transmission,we realized the abnormal transmission phenomenon with high efficiency at the incident wavelength of 532 nm.Three different anomalous transmission phenomenon was realized according to the phase gradient.And the anomalous transmission angles are 33.7o,21.7o and 16o respectively,and the transmission rate was all greater than 85%.Furthermore,when the phase difference is set to 90o,the same anomalous transmission phenomenon is achieved through different combinations of cells of metasuraces,and the transmission efficiency successfully proves that the metasurfaces are very convenient and highly efficient in light modulation.Absorber,one of the important applications of metasurfaces,has important application value in the fields of heat transmitter and solar energy.Our absorber was designed by using Au.And the influence of different geometrical parameters on the absorptivity was tested by simulations.Consequently,the high-efficiency absorber in ultraviolet and visible bands was realized,and the excitation of surface Surface Plasmons Polariton was determined by electric field analysis.Most of the previous researches on beam splitter are realized by reflect-array metasurfaces and focused on the near-infrared wavelengths.we realized a beam splitter in the visible wavelengths by using transmit-array metasurfaces with polarization sensitivity,which is also can be applied as a high-performance refractive index sensor.According to the rotational symmetry of our structure,the beam splitter is able to offer selectable scattering directions for x-/y-polarized incident light.For refractive index sensors with transmit-array structure,it is necessary to realize the shifts of resonance peak in transmission spectrum or reflection spectrum within a certain range of refractive index.Our biosensor can detect the refractive index from 1.30 to 1.39 with high FOM* 92333.