Error analysis of a Shack-Hartmann wavefront sensor

摘要

We analyzed the measurement errors of a Shack-Hartmann sensor caused by two major factors. One is caused by the collimation lens aberration change which occurs due to the light path shift in the collimation lens. Another is the defocus of the collimation lens due to ambient temperature change. To obtain the aberration change caused by the light path shift, we apply the primary aberration to the collimation lens aberration at arbitrary light path. To obtain the defocus by ambient temperature change, we derived a formula as a function of the temperature dependence of the refractive indices and the linear expansion coefficients of the lens and the lens mount. Measurement errors of a Shack-Hartmann sensor are estimated by both methods of ray trace and the present error analysis to examine the performance. The results show good agreement with the measurement error of the light path shift and the temperature change. This analysis is effective for analysis of the measurement error of the sensor, which can be utilized for reducing the residual measurement error.