A system and method for generating superoscillating optical needles based on sharp edge diffraction

Abstract

The invention discloses a system for generating a super-oscillating light needle based on sharp edge diffraction, which includes: a light source for generating monochromatic laser light; a lens for focusing the laser light and forming collimated plane light waves in the focal depth region; sharp edge The diffraction component is used to absorb the central part of the collimated plane light wave, and produces a super-oscillating focused light field due to sharp edge diffraction; the objective lens group is used to collect and amplify the super-oscillating focused light field; the camera is used to collect and record through the objective lens group collected superoscillating focused light fields. The invention proposes a simple and feasible system and method for generating a super-oscillating optical needle based on sharp-edge diffraction. Combined with sharp-edged metal discs or rings, the generation of super-oscillating light needles on the order of hundreds of nanometers can be realized. The system has a simple structure, flexible operation, stability and low cost, and has significant practical value.

Description

technical field [0001] The invention relates to the technical field of generation of super-oscillating optical needles, in particular to a system and method for generating super-oscillating optical needles based on sharp edge diffraction. Background technique [0002] The concept of superoscillation appears in the concept of weak measurement in quantum mechanics: the wave value of light waves obtained by local measurement in space may not exist in the range of measurement results in space as a whole. In 2006, Berry of the University of Bristol and his collaborators connected the concept of quantum super-oscillation with optical super-resolution for the first time, pointing out theoretically that using specially designed optical micro-nano structures (such as sub-wavelength grating structures) on the incident plane The amplitude of the light field is modulated, and the modulated diffractive light field can achieve sub-wavelength optical super-diffraction-limited focusing in t...

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Problems solved by technology

[0004] However, the structure of the super-oscillating components used above is very complicated, and it is generally necessary to etch thousands of nanometer-sized structural units on the metal film with a micron size. In the design process, it often needs to rely on optimization Algorithms to obtain the optimal superoscillation structure parameters, and the designed structure lacks a physical explanation for the superoscillation focused spot

In addition, from the existing research results, it can be seen that the current super-diffraction focused spot size is difficult to break through 0.3λ, and it is urgent to invent a simpler method to generate a smaller super-oscillation focused spot

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