A Design Method of Metal Film Superoscillating Ring Plate with Unequal Ring Width

Abstract

The invention discloses a method for designing a metal film super-oscillation ring belt sheet with unequal ring widths. An optimization target is established according to the distribution characteristics of the required diffracted light field under the condition of fixed-wavelength laser vertical illumination, an optimization target and micro-nano processing conditions are utilized to set parameters of the metal film super-oscillation ring band sheet, and a vector angular spectrum theory and a fast Hankel transform algorithm are utilized to calculate each polarization electric field componentand light field intensity distribution behind the super-oscillation annulus sheet; a fitness function model is established in combination with a diffraction light field optimization target; and the fitness of each girdle sheet is calculated, the width of each girdle of each girdle sheet is optimized and adjusted by adopting a particle position search method and combining mutation operation in a genetic algorithm, and finally the metal film super-oscillation girdle sheet which is closest to or meets the requirement of an optimization target through iterative operation is solved. The optimization method of particle position search is adopted based on the ring band structure with unequal ring widths so that the metal film super-oscillation ring band sheet with fewer ring bands and better performance can be optimized.

Description

technical field [0001] The invention belongs to the technical field of micro-nano optics and nano-photonics, and in particular relates to a design method for a super-oscillating ring-band plate of metal films with unequal ring widths. Background technique [0002] Affected by the diffraction limit, any conventional optical system or optical instrument can resolve the smallest detail of an object as d 0 =λ / (2NA), where λ is the illumination wavelength and NA is the numerical aperture of the optical system. The phenomenon of superoscillation refers to the existence of a band-limited function whose oscillation frequency in the local area is much larger than the maximum frequency component contained in it. Using optical superoscillation (Optical Superoscillation) can form a spot with a size smaller than the diffraction limit in the local space. Achieve super-resolution focusing that breaks through the diffraction limit. In recent years, the method of super-resolution focusing ...

AI Technical Summary

Problems solved by technology

Its disadvantages are: first of all, under the premise of equal ring width, the ring width of each ring must be an integer multiple of the minimum ring width, which limits the final optimization degree of the ring to a certain extent

[0008] It can be seen that the existing optimization algorithms for super-oscillating rings, namely the binary-based particle swarm optimization algorithm and the binary-based genetic algorithm, the optimization targets focus on metal film super-oscillating rings of equal ring width or medium super-oscillating rings of equal ring width slices, the optimization object is the coding of the transmittance of each annular zone, and there are certain limitations

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