A comparative study on the chromatic dispersions and the interactions with ultrashort pulses in epsilon-near-zero (ENZ) transparent conducting oxides (TCOs) is theoretically presented. The ENZ TCOs exhibit rapidly varying and unprecedentedly large $N\mathrm{th}$-order dispersions in the ENZ region, which is exclusive to ENZ plasmonic materials. However, it is found that in both physical and mathematical senses, the concepts of high $N\mathrm{th}$-order chromatic dispersions are inapplicable for ENZ TCOs with Drude-like permittivity. Subsequently, the impacts of the complex permittivity dispersion profiles on ultrashort pulse interactions are discussed. Comparisons are made between propagation patterns in an ENZ AZO waveguide obtained from the nonlinear Schrödinger equation (NLSE) and Maxwell's equations, as well as between interactions of femtosecond pulses with different temporal widths in a subwavelength ENZ AZO slab. Results show that the well-received NLSE is not suitable for modeling ENZ TCOs in either case, and subwavelength interaction patterns with different pulse widths are quite different, where the shorter pulse can excite stronger localized resonance.

• Received 20 March 2020
• Accepted 1 October 2020

DOI:https://doi.org/10.1103/PhysRevA.102.053503