Fabrication of the optical lens on single-crystal germanium surfaces using the laser-assisted diamond turning

Single-crystal germanium, as an excellent infrared optical material, has been widely applied in X-ray monochromators, night vision systems, and gamma radiation detectors. However, how to obtain high-quality optical lenses on their surfaces still faces challenges due to their hard and brittle properties. To this end, this paper proposes the in situ laser-assisted diamond turning (ILADT) process, which is the combination of a laser heating technique and a single-point diamond turning process. The in situ laser heating technique is employed to enhance the surface quality of the workpiece material, while the single-point diamond turning process is utilized to fabricate optical lenses. Experimental results showed that optical lenses with high surface quality were successfully machined. The profile error is 0.135 μm, indicating the high machining accuracy. The surface roughness Sa of the aspheric lens is 0.909 nm, indicating the high machining quality achieved by the proposed ILADT process. Therefore, this study provides an effective approach for producing high-quality optical lenses on single-crystal germanium surfaces, which holds great promise for future applications in the manufacturing of optical lenses with exceptional quality.