Design and Development of Shack-Hartmann Surface Deformation Measuring System

With the development of precision technologies, measuring methods with high resolution have become more and more important for the past few years. Due to the advantages of non-contact and high resolution of optical measurement, it has been applied to precision engineering for several years. Shack-Hartmann wavefront sensor (SHWS) can precisely detect the optical path difference of the light beam. By using the transmissive optical setup, it can measure the wavefront aberration caused by lens and atmosphere. Also, it can measure the surface topography by applying the reflective optical setup. A tunable SHWS with high resolution is designed in this paper. Shack- Hartmann deformation measuring system is also constructed to measure the surface topography of the piezoelectric components. The optical setup of the system is analyzed by the optical simulation software. The components of the system are optimized by the simulation results, which are also used to compare with the experimental results. Reflective optical setup is applied in this paper to measure the surface deformation, and a collimated beam is used as a reference beam. Providing voltage, from -50 V to 50 V, is applied to piezoelectric components to make them deform. The designed system is applied to measure the deformation of the surface. The profile of the deformed surface can be obtained by measuring the change of wavefront of the reflective beam. Finally, the accuracy of tunable sensor is obtained to 0.203 λ by experiments. The precision reaches 0.032 λ, and the resolution reaches 0.033 λ.