Fabrication of Electroless Nickel Coated X-ray Ellipsoidal Mirrors with Hybrid Metrology Method combining CGH and Contact Profilometer

Ellipsoidal mirrors are essential for high-performance X-ray focusing. A hybrid metrology method combining computer-generated hologram (CGH) interferometry and contact profilometry to enable accurate figure measurement and fabrication for ellipsoidal mirrors is proposed. Contact profilometry is used to extract errors that would otherwise be misinterpreted as alignment aberrations in CGH, and to inform the selection of appropriate alignment aberrations decoupling strategies. Using this method, we fabricated an ellipsoidal mirror with a final figure error below 20 nm RMS, while conventional CGH reported a result below 10 nm RMS. This approach improves measurement reliability and supports high-precision X-ray mirror manufacturing.