Tunneling time in a conjugate matched pair consisting of ε-negative and μ-negative materials

Tunneling time of electromagnetic wave propagating through a conjugate matched pair consisting of ε-negative and μ-negative materials is theoretically studied, where different tunneling parameters are considered. It is found that the tunneling pair structure can work as a special sub-wavelength open cavity; the quality factor of the tunneling mode varies with different parameters which decide the stored electromagnetic energy inside the cavity. The transient process of the complete tunneling mode is quantitatively described by the charging up characteristic time, which increases exponentially with the thickness of the cavity and linearly with the stored electromagnetic energy. Finite-difference time-domain simulations are in a good agreement with theoretical results.