Reflective terahertz time-domain spectroscopy measurement on the stripe-ordered superconductor La${}_{1.84-y}$Nd${}_y$Sr${}_{0.16}$CuO${}_4$

We measured reflectivity on static stripe-ordered La${}_{1.84-y}$Nd${}_y$Sr${}_{0.16}$CuO${}_4$ (LNSCO) $y$,=,0.1, 0.2, 0.3, and 0.4 by means of reflective terahertz time-domain spectroscopy (THz-TDS) with electric field polarized along c-axis, in which one can obtain lower frequency information than the conventional Fourier transform type spectrometer. Recently, two-dimensional superconducting (2DSC) property \cite{tajima,schafgans,li}, intra-layer perfect conductivity not accompanied with inter-layer superconducting behavior, was reported on LNSCO ($x$,=0.15,,,$y$,$\ge$,0.2). We observed the existence of Josephson plasma edge, which suggests that 2DSC is not realized in these compounds.