The Effect of Light Source Uniformity for Imaging Ellipsometry Measurements

Recently, imaging ellipsometry shown a wide range of applications in a tremendous number of fields, such as material science and biomedicine. Better imaging quality helps improve measurements accuracy. However, light source of present imaging ellipsometer is usually non-uniform and its non-uniformity contributes to the systematic error. The dual microlens arrays (MLAs) can shape the non-uniform beam into a flat-field beam, effectively improving the uniformity of the light source. We simulated and calculated the ellipsometric parameters by non-uniform illumination and uniform illumination. The simulated wavelength was 400–700 nm. Mean squared error (MSE) was used to quantify the accuracy of the measurement results. The results show that a more uniform light source helps to improve the signal-to-noise ratio and measurement accuracy.