A generalized reflection-free domain-truncation method: transparent absorbing boundary

A generalized technique is developed to truncate the computational domain without reflection. It transforms the unbounded-space Maxwell's equations to a set of auxiliary equations in a closed domain. A reflection-free amplitude-reduction scheme applied over the entire computational domain reduces the auxiliary field components outwardly and makes them equal to zero at the closed boundary. No additional absorbing region surrounding the domain of interest is needed with this technique because the relationship between the physical fields and their auxiliary counterparts is explicitly known and the former can be found from the latter within the computational domain.