Free-form off-axis three-mirror optical antenna design with an integrated primary/tertiary-mirror structure

In order to improve the performance and simplify the structure of an optical antenna for a space laser communication system, we design a free-form off-axis three-mirror optical antenna with an integrated primary/tertiary-mirror structure. The adoption of the integrated primary/tertiary-mirror structure improves efficiency of light energy utilization and reduces the complexity of optical processing and assembly. The introduction of free-form optical elements and optical structure constraints helps to correct the off-axis aberration and realize a large field of view. The obtained optical antenna has the magnification of five times and field of view of 2.4^∘×2.4^∘. The image quality obtained here reaches the diffraction-limited level. At the communication wavelength of 808 nm, the wavefront error is better than λ/22, and the system has a high energy concentration. The proposed optical antenna could not only improve tracking accuracy of the optical antenna in space but also greatly reduce the complexity of the laser communication system. It has reference significance and application value for free-space laser communication.