Design And Research Of Fiber-tip Special Beam Device Based On All-dielectric Metasurface

The special fiber beam generator based on all-dielectric metasurface was proposed and demonstrated.Rectangular resonator arrays with different widths were designed and arranged on the core surface of multi-mode fiber or dual-core fiber respectively so that the metasurface can focus or deflect the transmission beam.The size of a single rectangular resonator is on the order of subwavelength,and full phase control of 0 to 2? can be achieved simply by changing its width.The design and simulation of the focal plane quality of multi-focus fiber lens were presented.In addition,the optical properties of micro-nano particles produced by dual-core optical tweezers in water were also analyzed and studied.The combination of fiber and metasurface is also a good way to dispense with alignment devices in optical paths.It has a wide range of applications in nanophotonics.The main contents are as follows:1.Multi-focus optical fiber lens based on interleaving meta-atoms or lens aperture division method.A metasurface structure composed of rectangular resonators is designed on the surface of multi-mode fiber,which can generate multiple focal points in the longitudinal direction.The focal length is consistent with the design purpose,which shows that the phase control of a single rectangular resonator is basically accurate.In addition,the focusing efficiency of optical fiber lens is relatively high,and the FWHMs of the focuses are close to the diffraction limit.The optical fiber lens can not only achieve multi-focus functionality at a single wavelength,but also maintain multiple focuses across the broad wavelength range.2.Optical power analysis based on dual-core optical fiber tweezers.It is composed of a dual-core optical fiber and a metasurface structure that can realize beam deflection.The additional phase of transmitted light is regulated by changing the width of the rectangular resonator.The wavefront phase with different deflection angles is designed and the deflection angle of transmitted light can vary from-60 degrees to 60 degrees.In the far field of the dual-core optical fiber,the two deflected beams converge and generate interference fringes.The interferometer light field has several horizontal capture points.As the deflection angle of the transmitted light decreases,the gradient force on nanoparticles decreases gradually.However,the dual-core optical tweezers still have the ability to capture nanoparticle,and its stability number is still more than 10.By changing the diameter of the nanoparticle,the optical force can be adjusted.