Entirely electromagnetic analysis of microlenses without a beam-shaping aperture

We suggest an approach for numerically studying the performance of cylindri cal microlenses without a beam-shaping aperture based on the boundary-eleme nt method (BEM). We divide the infinite microlens boundary into two compone nts: The first part is an infinite expanded flat interface excluding the cu rved interface, and the second part is only the originally curved microlens interface. The resulting transmitted field can be regarded as the composit ion of two fields: One is generated by the first boundary, and the other is contributed from the second boundary. We carry out numerical simulations f or two microlens systems, with or without aperture. We find that, for the n onapertured system, an ideal focusing feature is still observed; however, t he axial distribution of the transmitted field exhibits an oscillation, dif ferent from the apertured system. It is expected that the current approach may provide a useful technique for the analysis of micro-optical elements. (C) 2001 Optical Society of America.