Method for selectively exciting diffraction levels on basis of metasurface complex amplitude modulation

Abstract

The invention discloses a method for selectively exciting diffraction levels on the basis of metasurface complex amplitude modulation, and belongs to the field of micro-nano optics. The structure sizes of nano rectangular columns of metasurfaces are changed to obtain amplitudes and dynamic phase information of target light fields, and azimuth angles theta of the nano rectangular columns of the metasurfaces are determined, and accordingly phases of the target light fields can be modulated; the amplitudes and the phase information are combined with one another, and accordingly complex amplitudescan be arbitrarily regulated and controlled in a single pixel; the periods of the metasurfaces are determined, Fourier levels corresponding to all the selected diffraction levels are superimposed, accordingly, complex amplitude information of various unit structures of the metasurfaces can be set, and the spatial propagation diffraction levels can be selectively excited. The method has the advantages that amplitude values of the target light fields can be processed by stages, and the phases of the target light fields can be continuously changed; the metasurface design and processing complexity can be lowered by the aid of the method, and the method can be widely applied to the fields of light field shaping, laser parallel processing, micro-nano optical detection and the like.

Description

technical field [0001] The invention relates to a diffraction order-independent selective excitation method, in particular to a method for generating complex amplitude modulation based on a medium metasurface, and belongs to the field of micro-nano optics. Background technique [0002] Metasurface is a kind of planar artificial electromagnetic material that uses artificial micro-nano structure design to achieve physical properties that do not exist in nature. The local light field response is changed by the strong optical response of sub-wavelength nano-antennas, resonant cavities and other structural units, thereby Realize wavefront modulation of subwavelength pixels. Different from the traditional method of using optical path accumulation to achieve phase change, metasurfaces can realize phase mutations on structures that are much smaller than the wavelength. In addition, metasurfaces can also realize the control of other optical parameters such as amplitude, polarization...

AI Technical Summary

Problems solved by technology

[0004] In order to solve the problem in the prior art that the selective excitation of diffraction orders cannot be achieved independently, the technical problem to be solved by a method for selective excitation of diffraction orders based on metasurface complex amplitude modulation disclosed in the present invention is to realize the spatial Selective Excitation of Propagated Diffraction Orders

Images