A nanometer scale alignment method of concentric spherical mirrors based on interferometry

A nanometer scale alignment method of spherical concentric mirrors based on dual-beam interferometry is proposed, which is also the method to measure the defocus of concentric spherical mirrors. In the process of aligning the concentric spherical mirrors, the defocus can be measured real time with nanometer scale error. The experimental result shows that the method can achieve the defocus of the spherical concentric mirrors several nanometers.