Study Of Super-diffraction Angle-resolved Telescope With Wavefront Digital Processing

With the continuous development of imaging technology,there is an increasing demand for the quality of the observed images in the field of space telescopy.From the previous studies,it is shown that the minimum detail of the optical system is limited by the diffraction properties of light,which is determined by the operating wavelength and the system aperture.How to use the fixed aperture optical systems to obtain superresolution imaging has become a hot issue for research.Many super-resolution techniques based on near-field optical field manipulation and structured light illumination have been reported,but they are not suitable for telescopic systems due to their characteristics.As a far-field markerless super-resolution imaging technique,super-oscillation imaging has a unique advantage in the field of telescopic imaging.However,the introduction of superoscillating devices into the optical path leads to the problem of extremely low energy utilization,which limits its practical applications.In this paper,we no longer pursue a more refined and clever design of the super-oscillator device,but use the method of digital image processing to propose a digital super-oscillation modulation algorithm based on the image spectrum to achieve the super resolution imaging.The main contents of the paper include:1、We designed the digital super-oscillation focal spot.The super-oscillation design method of inverse design is used to obtain the optical field of the pupil surface by predesigning the focal plane light field distribution and inversion.In terms of the superoscillation modulation type,the 0-π binary phase only type is selected and the linear programming is used to optimize the design,from which the phase modulation distribution to be applied to the pupil surface is calculated,and finally the superoscillation focal spot with 0.65 times diffraction limit is obtained in the focal plane.2、A digital super-oscillation modulation algorithm based on the image spectrum is proposed.The image acquired by the diffraction-limited system is first deconvoluted to recover its spectrum within the cutoff frequency,and then we take the digital superoscillation modulation on the recovered spectrum.Finally the super-resolved image is obtained by inverse Fourier transform.3、We completed super-resolution imaging optical simulation.Super-resolution imaging was performed for triple lines and triple holes structures in the subdiffraction limit,and the spectral law of comparing super-resolution images with diffraction-limited images was analyzed.The analysis of the law of the algorithm imaging contrast with the center spacing is completed using the two-hole structure,and the limit resolution of this algorithm is derived as 0.67 times the diffraction limit.