Method for constructing initial structure of athermal optical system based on particle swarm optimization algorithm

A method for constructing an initial structure of an athermal optical system based on particle swarm optimization algorithm, comprising following steps:

• step 1:
• calculating design specifications of the athermal optical system based on application requirements;
• the design specifications comprise various indicators, wherein the various indicators comprises operating wavelength band, operating temperature range, focal length, field of view angle, aperture, number of lenses, object distance, image distance, total system length, and image quality requirement;
• step 2:
• taking the design specifications from step 1 as an input, obtaining main structural parameters of the initial structure of the athermal optical system through the particle swarm optimization algorithm;
• step 2.1:
• according to the number of lenses in the athermal optical system, taking the focal length and chromatic aberration of the athermal optical system as preliminary optimization objectives, establishing an evaluation function F1 according to the preliminary optimization objectives, and obtaining a set of optimal solutions using the particle swarm optimization algorithm, the optimal solutions comprise optical power φ and Abbe number V of material of each lens;
• step 2.2:
• taking the chromatic aberration and thermal aberration of the athermal optical system as optimization objectives, and establishing an evaluation function F2 according to the optimization objectives;
• substituting the optimal solutions obtained in step 2.1 into the evaluation function F2, optimizing an material combination of the athermal optical system using the particle swarm optimization algorithm, and obtaining a set of optimal solutions, including the Abbe number V of material, relative dispersion P, and thermal aberration coefficient γ of each lens;
• step 2.3:
• taking the focal length of the athermal optical system as a optimization objective, and establishing an evaluation function F3 according to the optimization objective;
• substituting the optimal solutions obtained in steps 2.1 and 2.2 into the evaluation function F3, optimizing curvature radius of each lens using the particle swarm optimization algorithm, and obtaining a set of optimal solutions, including a first surface curvature radius and a second surface curvature radius of each lens;
• step 2.4:
• taking the optical power φ of each lens obtained in step 2.1, as well as the optimal solutions obtained in step 2.2 and step 2.3, as the main structural parameters for the initial structure of the athermal optical system;
• step 3:
• inputting the main structural parameters of the initial structure obtained in step 2.4 into optical design software, further adjusting the curvature radius, thickness, and air gap of each lens, analyzing image quality of the initial structure, and obtaining the initial structure of the athermal optical system.