Fumeaux, C.Lin, H.Serita, K.Withayachumnankul, W.Kaufmann, T.Tonouchi, M.Abbott, D.2012-11-082012-11-082012Optics Express, 2012; 20(16):18397-184141094-40871094-4087http://hdl.handle.net/2440/74104The process of terahertz generation through optical rectification in a nonlinear crystal is modeled using discretized equivalent current sources. The equivalent terahertz sources are distributed in the active volume and computed based on a separately modeled near-infrared pump beam. This approach can be used to define an appropriate excitation for full-wave electromagnetic numerical simulations of the generated terahertz radiation. This enables predictive modeling of the near-field interactions of the terahertz beam with micro-structured samples, e.g. in a near-field time-resolved microscopy system. The distributed source model is described in detail, and an implementation in a particular full-wave simulation tool is presented. The numerical results are then validated through a series of measurements on square apertures. The general principle can be applied to other nonlinear processes with possible implementation in any full-wave numerical electromagnetic solver.en© 2012 OSATerahertz imagingSpectroscopy, terahertzAperturesNear-field microscopyJournal article002012145510.1364/OE.20.0183970003073563001112-s2.0-8486458592023463Fumeaux, C. [0000-0001-6831-7213]Withayachumnankul, W. [0000-0003-1155-567X]Abbott, D. [0000-0002-0945-2674]