Research On The Control Characteristics Of Light Field Of Aberration Plane Supercritical Lens

Optical microscopic imaging is one of the most widely studied and applied imaging methods for many years,but its imaging resolution is limited by diffraction limit due to the nature of light fluctuation.The focus and imaging of super-resolution by breaking through the diffraction limit has always been one of the hot and difficult points in scientific research,and will have a far-reaching impact on a wide range of research fields.In recent years,the development of optical superoscillation has opened up a new idea of pure optical far-field superresolution imaging technology.By carefully controlling the distribution of the diffracted light field in space,sub-diffracted light spots with superoscillatory characteristics can be obtained in the far field.The advantage of this imaging technology is that it does not involve evanescent wave in the imaging process,does not require ultra-close working distance,and has no specific requirements or restrictions on imaging samples,lighting conditions and application environment.Super-oscillation lenses(SOLs)and supercritical lenses(SCLs),as the typical representatives of these technologies,have been widely studied by researchers in the field of diffractive optics and nanophotonics.In a variety of research works,they have fully proved the light field regulation ability of these lenses in the far field beyond the diffraction limit.Based on the current research status of SCL,this paper carries out research on the correction method of off-axis aberration of SCL.In addition,this paper proposed and experimentally demonstrated an environment-robust immersion SCL,which can work in a variety of immersion environments.The research content of this paper mainly includes the following aspects:(1)In this paper,two phase modulation modes of double layer and single layer are designed to correct the off-axis aberration of supercritical lens.In this paper,an algorithm is developed to optimize the off-axis aberration of a plane diffraction lens,and a correction layer structure matching with a phase type plane diffraction lens is designed.The phase distribution of the correction layer structure is obtained by using the iterative optimization algorithm,and the aberration correction is realized by a double-layer structure matching with a focusing lens.Through the optimization algorithm,the phase structure of the correction layer is combined with the phase of the focusing lens to form a phase type planar hyperlens with single-layer compound aberration,which can realize the large angle off-axis scanning imaging of the illumination light.Firstly,the ability of the designed aberration correction method to the diffraction-limited planar lens was proved.For a large aperture Fresnel zone plate(FZP)with a diameter of 100 ?m and a numerical aperture of 0.82,the aberration correction in the range of±30° is achieved by using two kinds of double layer and single layer phase scheme aberration methods.Secondly,for SCL with numerical aperture less than 0.7,the single-layer aberration method is used to obtain the foci without aberration beyond the diffraction limit within the incident angle range of ±10°.(2)The current studies on the modulation of subdiffractive limited light are only applicable to specific single immersion environment,and the imaging objective can only be used with the corresponding immersion medium.Changing the immersion environment will seriously reduce its focusing performance and limit its application scenarios.In this paper,a multi-objective optimization algorithm based on different imaging media is established,and an immersed supercritical lens is designed which is robust to the imaging media.In addition,sub-diffractive focusing spots with constant size can be obtained in different imaging media.Sub-diffraction limited focusing effect has been experimentally demonstrated in commonly used media including air,water,and oil with refractive indices of 1.0,1.33,and 1.51,respectively.Moreover,the effective numerical aperture of this lens can be maintained at a fixed value of around 0.83,bringing a unique advantage that the lateral size of the focal spots exhibits a similar value of317±7 nm in all three media.Our demonstration provides the feasibility of immersion SCL in various application scenarios with multi-immersion environments,such as bioimaging,light trapping,and optical storage.