Optical Surface Error Evaluation Method Based On Fractal Theory

In the application of laser technology about the development of modern, precision optical systems have a great demand for advanced optical components, such as laser fusion devices, high-energy laser, infrared thermal imaging, satellites and so on, and surface quality of the optical elements are increasingly high requirements. Numerous studies show that the surface quality of the optical element can cause huge impact to the entire optical system. High-quality optics not only requires advanced manufacturing technology, but also need a reasonable error detection methods to ensure the surface within a certain range, so as to satisfy the performance requirements, which are particularly important.Because of the traditional evaluation methods of optical surfaces has many deficiencies, based on the fractal structure of the optical surface, articles put forward the application of fractal theory to the surface error evaluation, establish the response model about polishing process parameters and the fractal dimension. The paper mainly does research in the optical surface error evaluation methods, response surface models about processing parameters and the fractal dimension. The main contents include:1.Analysis and comparison of the advantages and disadvantages of conventional evaluation methods of optical surface, based on the presence of the optical surface fractal structure, proposed fractal theory to evaluate the optical surface error.2.Simulating each fractal dimension calculation methods’calculation precision and applicable occasions, analyze the fractal characteristics of optical surfaces, An approximate linear relationship between the fractal dimension of the optical surfaces of different materials and traditional evaluation parameters is verified by experiments.3.CMP polishing tests carried out to establish the CMP polishing parameters and fractal dimension of the first and second order response surface model by RMS, seeking the most processing parameters.