Field-stitching boundary element method for accurate and rapid vectorial diffraction analysis of large-sized one-dimensional diffractive optical elements

We propose a field-stitching boundary element method (FSBEM) for diffraction analyses for large diffractive optical elements (DOEs). A field stitching (FS) method separately computes the divided sections of a large DOE and provides the field distribution without field mismatching. However, a divided section must be largely overlapped, which is not efficient in terms of computational resources. In the FSBEM, in addition to spatial division, the electromagnetic field is computed for each component-the reflected, difference, and stitching fields-for rapid convergence of the solution. We validate the FSBEM by computing a one-dimensional DOE and evaluating the convergence property. The sample structure is also computed by the conventional FS method, and the advantages of the FSBEM are discussed.