Abstract
In order to numerically simulate the formation of hologram appearing in the in-line holography method with high precision, improvement for FDTD (2,4) method was proposed. Examination about the effect of improvement showed that proposed improvement remarkably suppress the phase error of electro-magnetic wave to negligible level even in the case where large-scale calculation domain is ordered to treat multiple scattering problems, while the ordinal FDTD (2,4) method causes serious error in such cases. In addition, Dey-Mittra method, which is one of the conformal FDTD methods, is combined with the above-mentioned FDTD (2,4) method with improvement in order to suppress the error associated with step-wise approximation of particle shape. At the next stage, examinations were carried out using the above-mentioned conformal FDTD (2,4) method, about the influence of closeness between two particles on the location error of reconstructed image in the in-line holography method. Results of numerical simulation showed that reconstructed images of particles are deformed when the distance between two particles is shortened, and error appears in the evaluation of particle location- Location error is decreased with elongation of distance between two particles when they go away in the perpendicular direction to incident beam. On the other hand, contrary tendency partly appears when two particles go away in the parallel direction with incident beam.
