Rigorous diffraction theory applied to microlenses

In this paper, we discuss the behaviour of small cylindrical microlenses, arranged in one-dimensional arrays and as single elements. For this purpose, we apply a standard rigorous diffraction theory, commonly used for diffraction gratings. We investigate the coupling effect between the elements. It turns out that single elements behave like periodic elements if the spacing is chosen correctly. Furthermore, we compute the complex transmission function by rigorous diffraction theory and compare them with classical theories (combined ray tracing and the thin-element approach). Finally, we discuss the focal properties of microlenses in the rigorous regime.