Infrared and Laser Engineering, Volume. 54, Issue 6, 20240524(2025)

Research on wide-field and high-resolution optical system using aberration theory

Xiaosong GUO, Yunlong WAN, Tong YANG, Lei YANG, and Hongbo XIE
Author Affiliations
  • Key Laboratory of Optoelectronics Information Technology (Ministry of Education), School of Precision Instruments and Optoelectronics Engineering, Tianjin University, Tianjin 300072, China
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    ObjectiveOptical imaging technology is widely used in military and civilian fields. With the deepening of application requirements, people hope to achieve more imaging details, larger imaging range, further detection target detection effect. This requires an optical system with higher resolution and wider field. For an imaging optical system, wide field and high resolution are difficult to meet at the same time. In order to obtain a large field imaging, the imaging resolution will be greatly reduced; On the contrary, to achieve a higher imaging resolution, the imaging field can only be reduced. At present, in order to achieve wide-field high-resolution imaging detection, the existing research methods are non-single aperture, non-single detector imaging, which is complex in structure, large in volume, and requires post-image processing and stitching, and it is also difficult to achieve real-time detection. However, the traditional single-aperture and single-detector optical imaging system is limited by the optical system aperture size, off-axis aberration and other factors. So it is difficult to meet the requirements of large field and high resolution detection. The wide field means that the optical system has a larger off-axis aberration, and the optical aberrations have a direct effect on the imaging resolution.MethodsTo solve the problem, a new method for constructing wide-field high-resolution systems is proposed. In the initial stage of design, the inverse telephoto structure is used as the starting point. The front and rear lenses of the structure are complicated and replaced with lens groups respectively to bear different aberrations. By tracing the main ray and the edge ray, the Seidel aberration expression of the system can be obtained. Seidel aberration is a function of the radius of curvature, lens spacing, air spacing and refractive index of the system. When the function is solved, some specific constraints are added to make the initial structure adapt to improve the resolution in the subsequent optimization process. The specific constraint is to control the angle of incident light at the stop, so that the angle difference of different aperture light in each field is less than a certain range. In addition, the constraints of the system itself should also be taken into account, and the optimal solution of the function under the corresponding constraints is finally obtained, which is the initial structure of the optical system. To improve the resolution, the initial structure was further optimized. The Seidel aberration of the initial structure has been corrected and balanced, but there is still a large residual wave aberration, and the MTF curve cannot approach the diffraction limit in the middle and high frequency band, in which the high-order aberration is the main influencing factor. The wave aberration of the system can be decomposed by Zernike polynomial, and the constraint conditions are set up to correct the specific order aberration, so that the PSF can be distributed centrally and the MTF can be improved.Results and DiscussionsAfter design, an optical system structure composed of 9 lenses is proposed. In the process of optimization, two kinds of high order aberration constraints are added to the original first order aberration optimization function based on high order spherical aberration and high order astigmatism. With the increase of the number of iteration optimization, the optimization function gradually becomes stable. After optimization, the absolute value of aberration decreases greatly, which realizes the purpose of controlling the balance of high order aberration. The final system field angle is 70 degrees, and the MTF curves are close to the diffraction limit, and better than 0.2 at 550 lp/mm, indicating that the system has high resolution and good imaging effect. The focal length of the system is 24.04 mm, the total length of the system is 208.8 mm, the diameter of the entrance pupil is 12.02 mm, the maximum optical diameter D=37.04 mm, and the system contains four high-order even aspheres.ConclusionsAberrations are the main factors affecting imaging resolution, so the study of aberration is the key to achieve high resolution with wide field. Based on Seidel's aberration theory and by controlling the angle of the diaphragm, an initial structure design of wide-field high-resolution imaging optical system is proposed. On this basis, a high order aberration correction algorithm based on Zernick polynomials is proposed. Through the constraint correction of some high order aberrations, the optimal path to improve the resolution is quickly found, and the high resolution imaging design of wide-field optical systems is realized. The method effectively solves the problem of low imaging resolution and difficult optimization design of wide-field optical system, and has certain reference value for wide-field optical system design. However, the method only considers some high-order aberrations, and the decomposition of aberrations is not complete. Therefore, further research is still necessary.

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    Xiaosong GUO, Yunlong WAN, Tong YANG, Lei YANG, Hongbo XIE. Research on wide-field and high-resolution optical system using aberration theory[J]. Infrared and Laser Engineering, 2025, 54(6): 20240524

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    Paper Information

    Category: Optical design and fabrication

    Received: Nov. 12, 2024

    Accepted: --

    Published Online: Jul. 1, 2025

    The Author Email:

    DOI:10.3788/IRLA20240524

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