Conditions for electric field enhancement in ε-near-zero Slabs under TM-polarized oblique incidence

Artificial composite materials have been proven to be viable candidates to increase the degrees of freedom in the interaction of electromagnetic (EM) fields with matter. Composite materials (MTMs) add very interesting possibilities to control EM waves from microwaves to optical frequencies. As a subset of MTMs, artificial composite materials that exhibit ε-near-zero (ENZ) properties have attracted a great deal of attention in view of their potential applications, including tunneling of electromagnetic energy, highly directional beaming, cloaking devices, boosting of optical nonlinearities and low-threshold nonlinear effects.