Delay times in a terahertz chiral metamaterial slab

We investigate the propagation of circularly polarized electromagnetic waves through a free-standing Omega particle chiral metamaterial slab and study the associated delay times: dwell time and group delay. Through this analysis, we observe different interactions of right- and left-circularly polarized waves in the terahertz frequency range (1-2.5 THz) with the resonant elements. As a consequence, the resonant-frequency group delay and dwell time of the right-circularly polarized wave are one or more orders of magnitude longer than those of the left. In addition, we compare the delay times obtained from rigorous numerical simulations with those calculated using the retrieved effective parameters. We find that the dwell time cannot be evaluated correctly from the effective medium approximation, while no such problems exist in the case of group delay