Wave-optical modeling beyond the Thin-Element-Approximation

The optical design and analysis of modern micro-optical elements with high index contrasts and large numerical apertures is still challenging, as fast and accurate wave-optical simulations beyond the Thin-Element-Approximation are required. We introduce a modified formulation of the Wave-Propagation-Method and assess its performance in comparison to different Beam-Propagation-Methods with respect to accuracy, required sampling densities, and computational performance. For typical micro-optical components, the Wave-Propagation-Method is found to be considerably faster and more accurate at even lower sampling densities compared to the different Beam-Propagation-Methods. This enables realistic wave-optical simulations beyond the Thin-Element-Approximation for micro-optical components. As an example, the modified Wave-Propagation Method is applied for in-line holographic measurements of strongly diffracting objects. From a direct comparison of experimental results and corresponding simulations, the geometric parameters of a test object could be retrieved with high accuracy.