Testing accuracy is an essential factor in determining the manufacturing accuracy of aspheric mirrors. Because of the complexity of the null compensation test, the coherent stray lights generated by multiple reflections and transmissions between optical elements and the crosstalk fringes generated by the multi-beam interference of the reference light, test light, and stray lights are superimposed on the interference fringes, resulting in reduced testing accuracy. Focusing on this problem, a simulation analysis method for crosstalk fringes based on ray-tracing and multi-beam interference in interference testing is proposed. The coordinates, amplitudes, and phases of the test light and stray lights on the transmission sphere are traced, and the crosstalk fringes and interference testing fringes and their positions, sizes, and intensity information are simulated via multi-beam interference. The influence of crosstalk fringes on interference fringes is determined. An experimental optical path is built to verify the correctness of the crosstalk fringe simulation method.

Six-degree-of-freedom industrial robots, known for their low cost and high flexibility, have been extensively applied in optical processing. Precise pose control in robot-based optical processing systems depends on the accurate calibration of the tool coordinate system. However, in robot magnetorheological finishing (Robot-MRF) systems, the spherical shape of the polishing wheel poses significant challenges in precisely identifying the working point on the tool’s surface. Traditional calibration methods, such as the four-point or six-point techniques, fail to accurately calibrate the tool coordinate system for MRF tools. To overcome this limitation, a laser tracker-based calibration method is proposed for parameter calibration of the Robot-MRF system. Experimental results show that this method achieves a maximum repeatability error of just 0.0505 mm, significantly improving the stability and reliability of the calibration results and meeting the high-precision processing requirements of MRF technology.

In order to meet the manufacturing requirements of modern space remote sensors for high-precision freeform optical parts, the grinding technology and its application were studied. The objective of this paper was to improve the application effect of traditional grinding technology in the processing of hard and brittle materials, and then apply it in specific fields. Therefore, the influence of key process factors such as cutting speed and removal depth on subsurface damage (SSD) was studied based on orthogonal experiments, and an improved grinding technology characterized by low SSD and high surface shape accuracy was formed. Then, the effect of this grinding technology was further verified by the high-precision manufacturing of freeform surfaces. A surface of a 130 mm diameter freeform surface was machined by improved grinding technology and combined polishing technology, the final root mean square of surface shape reached 12.1 nm. The improved grinding technology can reduce SSD from 20 μm to 10 μm, and improve the manufacturing efficiency of freeform surfaces above 30% when the cut speed is 20 m/s and the remove depth is 10 μm. The proposed technology can be applied to the extreme manufacturing of hard and brittle materials.

Null compensation interferometry is the primary testing method for the manufacture of ultra-high-precision aspheric mirrors. The crosstalk fringes generated by stray light in interferometry can affect accuracy and potentially prevent the testing from proceeding normally. Position errors include the decenter error, tilt error, and distance error. During the testing process, position errors will impact the testing accuracy and the crosstalk fringes generated by stray light. To determine the specific impact of position errors, we use the concept of Hindle shell testing of a convex aspheric mirror, and propose the simulation method of crosstalk fringes in null compensation interferometry. We also propose evaluation indices of crosstalk fringes in interferometry and simulate the influence of position errors on the crosstalk fringes. This work aims to help improve the design of compensation interferometry schemes, enhance the feasibility of the design, reduce engineering risks, and improve efficiency.